Histochemical techniques were employed to study the tissue distribution of hydrolytic enzymes in adult female Onchocerca fasciata (Filarioidea: Onchocercidae). Different tissues differed considerably in the localization and distribution of the six enzymes studied. Acid phosphatase (AcPase) activity was detected in the cuticle, hypodermis and reproductive organs. Alkaline phosphatase (AlkPase) activity was largely absent. Adenosine triphosphatase (ATPase) was found in the somatic musculature and muscles of the uterine ducts, whereas 5'-nucleotidase (5'-Nu) was restricted to young oocytes and dividing embryos in the female worm. Strong glucose-6-phosphatase (G-6-Pase) activity was demonstrated in the uterine epithelial cells and microfilariae, as was weak activity in the hypodermis. Naphthylamidase (NAM) activity was detected in the hypodermis, with lower activity occurring in the somatic musculature. The possible functions of these enzymes are discussed with respect to their location. The hydrolytic enzymes AcPase and NAM in the body wall are probably involved in absorptive-digestive functions, NAM in the somatic musculature may be concerned with tissue protein turnover, and ATPase, 5'-Nu and G-6-Pase may have a role in active transport and energy metabolism.
The activities of some key enzymes of the glycolytic and pentose phosphate pathways were investigated histochemically in adult female Onchocerca fasciata (Nematoda: Filarioidea). The distribution patterns of phosphofructokinase (PFK), aldolase (ALD), glyceraldehyde 3-phosphate dehydrogenase (G3PDH) and glucose 6-phosphate dehydrogenase (G6PDH) in different tissues of the worm were determined by employing NitroBlue Tetrazolium (NBT). The glycolytic enzymes PFK, ALD, and G3PDH were distributed throughout the hypodermal tissue, somatic muscles and reproductive organs. These enzyme activities were predominantly expressed in the hypodermal and reproductive tissues, both of which appeared to be metabolically more active than adjacent tissues. The high activities of the enzymes studied in the hypodermal tissue when compared with the minimal or low activity in the intestinal epithelium support the assumption that the worm's intestine, in contrast to the body wall, plays no significant role in the nutrient acquisition process. The results emphasize that both the glycolytic and hexose monophosphate pathways of carbohydrate metabolism are active components in energy production and biosynthetic processes in the various tissues of the worm. The functional significance of these glucose-metabolizing enzymes has been discussed with regard to their location in the tissues concerned.
Histochemistry studies of key dehydrogenases in the glycolytic pathway and related enzymes and the tricarboxylic acid (TCA)-cycle enzymes were carried out on adult female Onchocerca fasciata. The distribution pattern and enzymatic activities of 6-phosphogluconate dehydrogenase (6-GPDH), lactate dehydrogenase (LDH), mitochondrial glycerol-3-phosphate dehydrogenase (GPDH), nicotinamide adenine dinucleotide (phosphate) [NAD+(P)]-linked isocitrate dehydrogenase (ICDH), and NAD+(P)-linked malate dehydrogenase (MDH) in various tissues of the worm were determined. Moderate to intense enzyme activities were localized in three main areas, namely, the hypodermis, body-wall muscle, and reproductive tissues. Activity of the formazan reaction product was very low, if at all present, in the intestinal epithelium and was completely absent in the cuticle. On the basis of the present results and earlier observations, it is suggested that glycolysis leading to the end product lactate is the main energy-generating pathway in O. fasciata. The presence of significant activity of 6-GPDH indicates that the pentose-phosphate pathway might be operative in O. fasciata. In light of the activity of some of the TCA-cycle enzymes, ICDH and MDH, demonstrable in O. fasciata, it is possible that an additional pathway (pyruvate-succinate) of glucose metabolism via a reverse sequence of the TCA cycle may also be operative in the worm. The possible functional significance of the enzymes detected is discussed with respect to their location.
The activities of selected enzymes of the respiratory chain system in Onchocerca fasciata (Filarioidea: Onchocercidae) have been investigated histochemically. Thus, the localization and distributions of NADH dehydrogenase (EC 1.6.99.3), succinate dehydrogenase (SDH) (EC 1.3.99.1) and cytochrome oxidase (EC 1.9.3.1) were investigated in various tissues of the adult female worm by employing MTT, Nitro BT (dehydrogenases) and DAB (cytochrome oxidase). Different tissues varied considerably in their enzymatic activities. The hypodermis and reproductive tissues showed strong and identical localization of NADH and SDH dehydrogenase activities reflecting high metabolic rates. Little or no dehydrogenase activities were observed in the intestine and cuticle. In contrast to the two dehyrogenases, no activity was observed for cytochrome oxidase in any of the tissues in adult or embryonic stages of the worm. The significance of these results with respect to the energy metabolism of the worm is discussed. It is suggested that O. fasciata lacks a classical, mammalian-type respiratory pathway and that oxidative phosphorylation is of no importance as an energy generating pathway in this essentially anaerobic parasite.
a survey was conducted on the number of scientific publications written by the faculty members at the College of Medicine, Abha, over an eight-year period between 1988 and 1995. The survey showed that there were 139 publications during this period, and that they mostly covered local health problems of significant clinical interest to the region.The Medline-on-Silver-Platter system and the database of King Abdulaziz City for Science and Technology (KACST) were used as the sources. The database of KACST was accessed through the King Saud University Gulfnet terminals available at the College. The search parameters were Abha and Saudi Arabia. Publications cited in the 1996 Medline disc were not counted in the search because they were not yet complete. The results of the search were fed into a desktop computer. Another search using the Reference Manager software version 7.02 was used to extract the required publications. Final sorting of references was done manually to exclude duplicate articles, and other articles published elsewhere.The number of publications cited in the Medline database for the eight-year period (1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) was 114, while those cited by the KACST database was 25, consisting mainly of publications in local journals. The largest number of articles were published in 1992 and 1995 (39 and 33 respectively). The number of publications, though relatively modest, nevertheless represents an impressive source of information about the region from a junior college which began graduating doctors in 1987. It should also be mentioned that the actual number of publications is much larger than what has been cited from these two sources. A large amount of research work has been published in journals that are not listed by either the Medline System or by the KACST database.The significance of such research work is being reflected in the improving health services offered by the College, and in its contribution to the pool of knowledge in basic medical sciences.
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