Genetic Variation at 15 Autosomal STR Loci Among Seven Egyptian Populations.

Egypt is a transcontinental country containing substantial ethnic, cultural, and linguistic diversity among its people. This study was conducted to investigate the genetic variation at 15 AmpFlSTR Identifiler short tandem repeat (STR) loci, D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA, within and between seven Egyptian populations. Samples of 814 unrelated individuals from Northern Coast, Delta, Greater Cairo, Canal governorates, Northern Upper Egypt, Southern Upper Egypt, and Sinai were investigated. All loci were highly polymorphic in all sample populations. The data were analyzed to give information on allele frequencies and other population statistical parameters. After applying Bonferroni correction, the agreement with Hardy-Weinberg equilibrium (HWE) was confirmed for all loci (exact test), and for all loci with the exception of D3S1358, D19S433, and D18S51 (X2 test). The levels of genetic differentiation and the genetic relationships among populations were evaluated by coefficient of genetic differentiation (FST), AMOVA, and genetic distance of Nei. The most differentiated populations were found between Sinai and Southern Upper Egypt. These two populations showed the lowest within-population variation, whereas the population of Greater Cairo showed the highest within-population variation as indicated by the fixation index FIS. The varying levels of genetic relatedness among the populations in relation to their geographical distribution were analyzed using Mantel test. The results demonstrated that the effectiveness of STR markers enhances their value for identifying the genetic variation within and between Egyptian populations.

Ultrastructural organization of muscle fiber types and their distribution in the rat superior rectus extraocular muscle.

Extraocular muscles (EOMs) are unique as they show greater variation in anatomical and physiological properties than any other skeletal muscles. To investigate the muscle fiber types and to understand better the structure-function correlation of the extraocular muscles, the present study examined the ultrastructural characteristics of the superior rectus muscle of rat. The superior rectus muscle is organized into two layers: a central global layer of mainly large-diameter fibers and an outer C-shaped orbital layer of principally small-diameter fibers. Six morphologically distinct fiber types were identified within the superior rectus muscle. Four muscle fiber types, three single innervated fibers (SIFs) and one multiple innervated fiber (MIF), were recognized in the global layer. The single innervated fibers included red, white and intermediate fibers. They differed from one another with respect to diameter, mitochondrial size and distribution, sarcoplasmic reticulum and myofibrillar size. The orbital layer contained two distinct MIFs in addition to the red and intermediate SIFs. The orbital MIFs were categorized into low oxidative and high oxidative types according to their mitochondrial content and distribution. The highly specialized function of the superior rectus extraocular muscle is reflected in the multiplicity of its fiber types, which exhibit unique structural features. The unique ultrastructural features of the extraocular muscles and their possible relation to muscle function are discussed.

Efficacy of abamectin against the fowl tick, Argas (Persicargas) persicus (Oken, 1818) (Ixodoidea: Argasidae).

Abamectin, in aqueous solutions of dose rates 0.0625, 0.125, 0.25, 0.5, and 1 mL/L, was sprayed on different feeding stages of the tick Argas (P.) persicus. The results revealed a marked increase of immobile and dead male or female ticks following a single treatment with the above doses, particularly the higher ones, and during the 5 weeks after treatment. Abamectin seriously decreased the percentage of fed ticks as well as that of oviposition and hatching. A decrease in the amount of emitted coxal fluid was observed also following treatment. Although the amount of ingested blood increased following abamectin treatment, digestion remained similar. The study also revealed that spraying a dose of 0.5 mL/L of abamectin in fowl shelters, i.e., floor, walls, ceiling, etc., is sufficient to eradicate A. persicus population.

Histochemical analysis of muscle fiber types of rat superior rectus extraocular muscle.

Extraocular muscles (EOMs) represent a distinctive class among mammalian skeletal muscles in exhibiting unique anatomical and physiological properties. To gain insight into the basis for the unique structural/functional diversity of EOM fiber types and to explain their high fatigue resistance, rat superior rectus muscle (SRM) was studied using histochemical techniques. Muscle fibers were typed with regard to their oxidative and glycolytic profiles generated from succinic dehydrogenase (SDH) and phosphorylase activities in combination with their morphologic characteristics. Superior rectus muscle is organized into two layers, a central global layer (GL) of mainly large diameter fibers and an outer C-shaped orbital layer (OL) of principally small diameter fibers. Five muscle fiber types were recognized within the SRM: I, II, III, IV and V. In the global layer, four muscle fiber types were identified: type I (18.25±0.96µm; 32%) showed intermediate SDH (coarse type) and high phosphorylase activity. Type II fibers (14.45±0.82µm; 22%) exhibited high SDH (fine type) and intermediate phosphorylase activity. Low SDH (granular type) and high phosphorylase activity were demonstrated by type III fibers (22.65±1.73µm; 36%). Type IV fibers (26.24±1.32µm; 10%) were recognized by their low oxidative and glycolytic reactions. In the orbital region, only three muscle fiber types were recognized; fiber types I and II were found to compose approximately two-thirds of the layer. The third orbital fiber type (type V, 10.05±0.99µm) exhibited low SDH and low phosphorylase profiles. In this paper, the functional significance of the histochemical characteristics of the EOM fiber types is discussed.