Ashraf Mohamed Ali Mashaly

Sprouting interneurons in mushroom bodies of adult cricket brains

In crickets, neurogenesis persists throughout adulthood for certain local brain interneurons, the Kenyon cells in the mushroom bodies, which represent a prominent compartment for sensory integration, learning, and memory. Several classes of these neurons originate from a perikaryal layer, which includes a cluster of neuroblasts, surrounded by somata that provide the mushroom bodys columnar neuropil. We describe the form, distribution, and cytology of Kenyon cell groups in the process of generation and growth in comparison to developed parts of the mushroom bodies in adult crickets of the species Gryllus bimaculatus. A subset of growing Kenyon cells with sprouting processes has been distinguished from adjacent Kenyon cells by its prominent f‐actin labelling. Growth cone‐like elements are detected in the perikaryal layer and in their associated sprouting fiber bundles. Sprouting fibers distant from the perikarya contain ribosomes and rough endoplasmic reticulum not found in the dendritic processes of the calyx. A core of sprouting Kenyon cell processes is devoid of synapses and is not invaded by extrinsic neuronal elements. Measurements of fiber cross‐sections and counts of synapses and organelles suggest a continuous gradient of growth and maturation leading from the core of added new processes out to the periphery of mature Kenyon cell fiber groups. Our results are discussed in the context of Kenyon cell classification, growth dynamics, axonal fiber maturation, and function. J. Comp. Neurol. 508:153–174, 2008.

Zinc improves the immune function and the proliferation of lymphocytes in Cadmium-treated rats

The effects of Cadmium (Cd) exposure and the treatment with Zinc (Zn) on immune functions of splenocytes and cultured lymphocytes of rats were studied. The exposure of rats to Cd was at a dose of 2.2 mg/kg CdCl2, injected subcutaneously four times weekly for 2 months. Rats were supplemented with Zn (2.2 mg/kg ZnCl2, injected subcutaneously four times weekly for 2 months) one hour prior to Cd exposure. Spleens were removed and splenocytes were isolated and cultured. The proliferation capacity of lymphocytes and their homing to the spleen were studied. Ribonucleic acid (RNA) was extracted from stimulated lymphocytes in order to analyse gene expressions using RT-PCR. Accordingly, proliferation of lymphocytes was found to be suppressed in Cd-treated rats, both in vivo and in vitro. Zinc served to activate the proliferation of B and T lymphocytes in Cd-treated rats both in vivo and in vitro. Antigen-activated lymphocytes showed that Cd impaired the mRNA expression of CD68, Ccl22 and CXCL10. Zinc was not found to restore mRNA expression of these genes to the normal levels. Zinc was found to decrease the MDA level with replenishment of activity of key antioxidant enzymes and proteins in Cd-pre-treated animals significantly. Moreover, the histopathological examination of spleen samples also agreed with the molecular, immunological and redox findings. Hence, Zn is able to restore the normal structure, redox status and immunity in Cd-induced damage in the rat model system.

The trail pheromone of the venomous samsum ant, Pachycondyla sennaarensis

Abstract Ant species use branching networks of pheromone trails for orientation between nest and resources. The current study demonstrated that workers of the venomous samsum ant, Pachycondyla sennaarensis (Mayr) (Hymenoptera: Formicidae: Ponerinae), employ recruitment trail pheromones discharged from the Dufours gland. Secretions of other abdomen complex glands, as well as hindgut gland secretions, did not evoke trail following. The optimum concentration of trail pheromone was found to be 0.1 gland equivalent/40 cm trail. This concentration demonstrated effective longevity for about one hour. This study also showed that P. sennaarensis and Tapinoma simrothi each respond to the trail pheromones of the other species as well as their own.

Carrion beetles succession in three different habitats in Riyadh, Saudi Arabia

A main objective of the study is the establishment of a forensic entomological database for Riyadh, Saudi Arabia. Decomposition processes and beetle succession were analysed on rabbit carcasses in three different habitats (agricultural, desert and urban) in the period from May to July 2014. Due to the effects of the high temperature at the study sites, carrion reached the dry stage within 12 days in the agricultural habitat, and 6 days in the desert and urban habitats. A total of 125 beetles belonging to eight species and five families were collected during the decaying process, with their abundances increasing from the fresh to decay stages. The prevailing species belonged to the families of Dermestidae and Histeridae. It was not possible to confirm any definitive relationship between the occurrence of a single species and a particular stage of decomposition. The beetle communities were also not distinctively different between desert and urban habitats, but a distinct community was evident in the agriculture habitat. In addition, there were distinct beetle communities between the decay stage and the other stages. The dry stage recorded the lowest number of beetles. This study indicated that, the habitat type had an effect on the decay process and the abundance rate of the beetles.

Entomofaunal Succession Patterns on Burnt and Unburnt Rabbit Carrion

Abstract The influence of burning on the decomposition of rabbit carcasses and on insect succession was investigated in three different habitats (agricultural, desert, and urban) in order to provide data for estimating the postmortem interval (PMI). Each site had six carcasses divided into two groups of three rabbits, with the carcasses in one group being partially burned, while the others were not burned. Carrion reached the dry stage within 5 d in the desert and urban habitats and 13 d in the agricultural habitat. The unburnt and burnt carcasses also decomposed at a similar rate in the three study habitats. Adult dipteran and coleopteran insects were collected daily. A total of 24 species and 2,381 specimens were collected; of these, 732 specimens from 21 species were taken from the partially burnt carcasses and 1,649 specimens from 21 species from the unburnt carcasses. There were significantly distinct insect communities between the agricultural habitat and the desert and urban habitats. There were also significant differences in the insect communities between the decay stage and other stages, with fresh and dry stages recording the lowest number of insects. There were some species which only presented themselves during the decay stage of decomposition, namely, Platypalpus sp., Desmometopa varipalpis Malloch, Atherigona orientalis (Schiner), Atherigona yorki Deeming, Musca sorbens Weidemann, and Onthophagus nitidulus Klug. In addition, there were significant distinctions in the insect communities between unburnt carcasses and burnt carcasses. The presence of these distinctions means that it is possible to estimate the PMI from partially burnt rabbit carcasses.

Spontaneous behavioral rhythms in the isolated CNS of insects – Presenting new model systems

Three new model systems for the study of rhythm generation in the isolated insect central nervous system are presented. Natural behavioral rhythms are produced in these cases spontaneously in the isolated CNS. They can be monitored as output of motoneurons at peripheral nerves. Recording from the neurons of the pattern generating networks during this output gives insight into neural control principles of locust respiration, of hemolymph pumping in accessory pumping organs of crickets, and of crawling movements in larvae of the weevil Rhynchophorus ferrugineus.

Cryomazine concentration and host type effects on the biology of the southern cowpea weevil Callosobruchus maculatus F.

In this study we investigated the effects of different cryomazine concentrations and host type on the biology of the southern cowpea weevil Callosobruchus maculatus F. (Coleoptera: Bruchidae). Our results showed that increasing cryomazine concentration led to the increase in the average incubation period of eggs and low hatching rate, reaching the highest average of egg incubation period 13.25 days for insects reared on a mung beans treated with cryomazine concentration of 3 and 5%. The lowest average for incubation period reached 9.25 days when insects reared on cowpea treated with 1% concentration of cryomazine. Insect reared on peas treated with 5% cryomazine concentration had a lower average percentage of hatching eggs, 1.25% in comparison with the control (67.25%). The maximum average rate of eggs hatching reached 55% of insects reared on mung beans treated with 1% cryomazine concentration compared with the control (75%). High cryomazine concentration reduced the percentage of pupation and adult emergence; the average percentage reached 19.83 and 27.08%, compared with the control 87.33 and 88.5% respectively. Thus, increasing cryomazine concentration not only led to the increase in the average duration of larvae and pupae of insects bred to all nutritional hosts except peas where the insect was unable to complete its life cycle but also led to reduction in the percentage of pupation and adult emergence.

First Report of Necrophagous Insects on Human Corpses in Riyadh, Saudi Arabia

Abstract Necrophagous species of insects provide useful complementary data to estimate the postmortem interval in forensic cases. Here, for the first time, we report on insect specimens collected from human corpses in Riyadh, Kingdom of Saudi Arabia. During the study, 14 beetle larvae were collected from the outdoor corpse (case report one) and five flies and seven beetles were collected from the indoor corpse (case report two). Sequencing was performed to study the mitochondrial DNA (mtDNA) as the prospective basis of an identification technique. The sequencing focused on a section of the cytochrome oxidase I encoding region of mtDNA. Two beetle species, Dermestes frischii (Kugelann) and Dermestes maculatus (De Geer) (Coleoptera: Dermestidae), and one fly species, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), were identified. These results will be instrumental in the implementation of a Saudi database of forensically relevant insects.

Biological activity of Xanthium strumarium seed extracts on different cancer cell lines and Aedes caspius, Culex pipiens (Diptera: Culicidae)

Effects of methanol extracts of Xanthium strumarium on different cancer cell lines and on the mortality rates of Aedes caspius, Culex pipiens (Diptera: Culicidae) were investigated. Among the cell lines tested, the Jurkat cell line was the most sensitive to the methanol extract and ethyl acetate fraction, with reported LC50 values of 50.18 and 48.73 μg/ml respectively. Conversely, methanol extracts were not that toxic to the A549 cell line though the toxicity increased on further purification. The percentage of growth inhibition was dose dependent for the methanol extract and ethyl acetate fraction. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The results showed that methanol extracts of plant seeds caused 100% mortality of mosquito larvae at a concentration of 1000 μg/ml after 24 h of treatment. The LC50 and LC90 values of X. strumarium were found to be 531.07 and 905.95 μg/ml against Ae. caspius and 502.32 and 867.63 μg/ml against Cx. Pipiens, respectively. From the investigations, it was concluded that the crude extract of X. strumarium showed a weak potential for controlling the larval instars of Ae. caspius and Cx. pipiens. However, on further purification the extract lost the larvicidal activity. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The ethyl acetate fraction investigated in this study appears to have a weak larvicidal activity but a promising cytotoxic activity. Future studies will include purification and investigation in further detail of the action of X. strumarium on Cancer Cell Lines and mosquitoes.

Differential Diptera Succession Patterns on Decomposed Rabbit Carcasses in Three Different Habitats

Abstract This study describes for the first time the necrophagous Diptera attracted to rabbit carcasses in three distinct habitats in Riyadh, Kingdom of Saudi Arabia (KSA). A mean number of 1,427 flies belonging to 8 families and 16 species were collected during the decomposition process of the rabbits at the three different sites. Carcasses in the agricultural habitat attracted 1,146 flies from 7 families and 14 species, compared to carcasses in the urban site, which attracted 249 flies from 5 families and 9 species. Carcasses in the desert site attracted the lowest number (28 flies from 4 families and 5 species). In the agricultural and desert sites, flies were represented at all decomposition stages. Also, in the urban site, flies were represented at all stages except the fresh and dry stages. Lucilia sericata Meigen was the most abundant species occurring in both the agricultural and desert sites, while Musca domestica L. was the most abundant species occurring in the urban site. The evidence presented here, therefore, suggests that L. sericata and M. domestica are potentially useful species for estimating minimal postmortem intervals in this region of KSA.