Some molecular aspects in schistosomiasis mansoni and toxoplasmosis.

The IL-2 and IL-4 cytokines production represent cellular Th1 & Th2 immune responses respectively were associated with chronic schistosomiasis mansoni (stages 1-4) and chronic toxoplasmosis gondii. In the hepatosplenic schistosomiasis, the level of IL-2 and disease stage increased in parallel (P<0.05, <0.01, <0.01 & <0.001 in stages 1, 2, 3 & 4 respectively), whereas, IL-4 was highly significantly increased in stage 1 than control (P<0.001), then decreased to lower levels. The mean concentrations of IL-2 & IL-4 in patients with T. gondii were higher compared to control being more marked in IL-2 (P<0.001) versus IL-4 (P< 0.01). The data indicated that there are patterns of cytokine expression characteristic of type 1 & type 2 responses in vivo, with the ultimate goal of being able to manipulate the response to minimize inflammation and fibrosis for clinical benefit.

Detection of altered secondary lymphoid-tissue chemkine responsiveness in Balb/c mice infected with Schistosoma mansoni.

To determine the extent to which Balb/c mice splenic T cells were affected by S. mansoni infection, this study aims to investigate the ability of the T cells to produce interferon (IFN)-&, and their chemotactic ability at 7 weeks post-infection. The splenic T cells were capable of producing levels of IFN-& comparable with splenic T cells from naive mice. However, the T cells exhibited altered chemotactic activity, as evidenced by an inability to respond to secondary lymphoid-tissue chemokine (SLC/CCL21). Although no difference in chemokine expression was found between the spleens of infected versus control mice, chemokine production was greater in the livers of infected versus control mice. Collectively, these data indicate that Balb/c mice with 7-wk S. mansoni infection possess splenic T cells with altered chemotactic activity and that the alterations may be a consequence of granulomatous response in the liver.

Evaluation of the role of some parasitic infections as a cause of acute and chronic hepatic diseases.

A total of 200 patients with acute and chronic hepatic diseases and 100 apparently normal cross-matched controls were examined for the parasitic cause. The IHAT showed 3% had hydatid cysts, 3% had fascioliasis and 53.5% had schistosomiasis. However, no eggs were detected in the fascioliasis patients and only 4 & 3 cases showed S. mansoni and S. haematobium eggs in stools & urines respectively. ELISA showed 10% with visceral larva migrans & 65.5% with toxoplasmosis (IgG, IgM or both). On the other hand, 27% of the controls showed antibodies against toxoplasmosis.

Studies on the megatrypanum trypanosomes of the Egyptian bat (Pipistrellum kuhli) from Sohag Governorate, Egypt.

Out of 150 Egyptian bats (Pipistrellus Kuhli) hunted in the premises of Sohag City, 60 (40%) were harbouring typanosomes of the subgenus Megatypanum (Hoare, 1964). They were T. M. heybergi (Rodhian, 1923), T. M. possoai (Dean and Sugary, 1963) and T. M. magadermae (Wenyon, 1990).

A microfilaria in a stray cat from Assiut, Egypt.

During a survey for helminth parasites among stray cats in Assiut area, microfilariae were detected. The morphology of the microfilarias was described.

Effect of inoculation with n(2)-fixing spirilla and azotobacter on nitrogenase activity on roots of maize grown under subtropical conditions.

Inoculated and non-inoculated seedlings of maize were grown in fertile clayloam soils of Egypt and Belgium under subtropical conditions provided in a greenhouse. Acetylene-reducing activity and microbial counts were determined during a period ranging from 6 to 12 weeks after sowing. Irrespective of soil origin, N(2)-fixing spirilla and Azotobacter were common under maize cultivation. Inoculation resulted in a transitional increase in their numbers at early stages of growth. Nitrogenase activity was not detected in the rhizosphere of young plants. The maximum activities measured (81 to 1,436 nmol of C(2)H(4) g h) occurred close to the 50 to 70% silking stage. Inoculation with N(2)-fixing spirilla, particularly in Nile Delta soil, doubled the amount of N(2) fixed in a late period of growth (12 weeks), whereas inoculation with Azotobacter had no noticeable effect.

Associative symbiosis of Azotobacter chroococcum and higher plants.

The association between a selected strain of Azotobacter chroococcum and seven plants was investigated in water cultures under sterile conditions. Azotobacter population progressively increased in the nutrient solution and on the rhizoplane. Microbial propagation depends on the type of plant, being much higher in presence of wheat, followed by barley, maize, broad bean, and cotton, while in presence of fenugreek and lentil lower rates of multiplication were recorded. Inoculation increased the dry weight of plants by 5--12% and in length by 3--18% in addition to increased nitrogen content of plants and nutrient solution. Nitrogen balance showed no significant change in systems devoid of Azotobacter, but association between plants and the microorganism invariably showed positive results. The extent of N2-fixation depends on the type of plants; higher gains were recorded in presence of non-leguminous plants.

Effect of Azotobacter inoculation on plant growth and soil nitrogen.

The validity of seed bacterization with Azotobacter chroococcum in soils of variable densities of naturally present azotobacters was studied. Inoculation of barley grains had no effect on counts of total microflora, neither in rhizosphere nor in root-free soil, but significantly increased Azotobacter population, especially in the rhizosphere. The rate of colonization in the root region was much higher when soil initially harboured low Azotobacter densities. Bacterization improved plant growth and increased soil nitrogen through nitrogen fixation. Nitrogen balance in soils showed higher gains in the inoculated treatments over the uninoculated analogues of 30--98 ppm.

Effect of organic matter supplementation on nitrogen transformations in soils. I. Chemical and bacteriological changes.

The effect of supplementation with different organic materials on nitrogen transformations and on certain bacterial groups in soil was studied. Addition of wide C/N ratio organic matter, sawdust and maize stalks prevented NO3-N from being lost through leaching out or dentrification and favoured the development of Azotobacter and N2-fixing clostridia that in turn resulted in marked gains in nitrogen through N2-fixation. Nitrifying bacteria were adversely affected. Application of such materials together with high amounts of NH4NO3 lessened nitrogen losses in drainage water but increased losses through denitrification. Nitrogen-rich organic matter resulted in higher losses in nitrates from soils in comparison to those of wide C/N ratio organic materials.

Effect of organic matter supplementation on nitrogen transformations in soils. II. Nitrogen balance and yield.

Under controlled laboratory conditions, the effect of the application of uncomposted plant materials (sawdust and maize stalks) or horns and hooves (narrow C/N ratio) on soil nitrogen and plant growth was investigated. From nitrogen balance calculations it was found that the addition of the wide C/N ratio materials alone either increased soil nitrogen through N2-fixation or lessened nitrogen loss through denitrification. Although such materials resulted in the immobilisation of mineral nitrogen, no nitrogen starvation symptoms were noted on the growing plants. Negative nitrogen balances were usually obtained when soils received mineral nitrogen fertilizers either alone or together with maize stalks or supplemented with the narrow C/N ratio organic material.

Seed inoculation with Azotobacter chroococcum in sand cultures and its effect on nitrogen balance.

The effect of bacterization of barley grains with a selected strain of Azotobacter chroococcum was studied. In nitrogen-deficient sand, seed inoculation increased plant length, dry weight, nitrogen content in addition to a significant increase in soil nitrogen. The density of the organism on grains had a slight positive effect. Irrigation with KNO3-containing nutrient solution suppressed nitrogen fixation, but inoculation still had a pronounced stimulating effect on plants. In presence of mixed soil microflora the beneficial effect of bacterization was less than in monobacterial cultures. Azotobacters naturally present in soil also colonized in heavy densities on the rhizoplane, but their effect on plant growth and soil nitrogen were less if compared with that resulting from bacterization.

Temperature adaptability of nitrifying bacteria in soils of Egypt.

Five soils, representing different locations in Egypt that vary in their climatic conditions, were studied for their nitrifying capacity under different temperature levels. The optimum temperature was 30 degrees C, followed by 20 degrees C. At both temperatures no differences among soils in their nitrifying capacity were observed, and nitrification approached completion after 4 and 6 weeks, respectively. NH4-N osication proceeded at lower rates of 10 degrees and 40 degrees C, but variations among soils in their capacity were observed. At 50 degrees C nitrification took place at fairly high rates in one soil, representing an area characterized by its extreme aridity and high temperature.

Evaluation of some biological tests as parameters for microbial activities in soils. I. Laboratory experiments.

The experiments were confined to the effects of the addition of different sources of carbon (glucose, wheat straw, and sawdust) on the microbial activities in soils: loamy sand, loam and saline clay were used. The parameters used for this purpose were total bacterial counts, dehydrogenase test, CO2 evolution, and oxidation of organic carbon. Salinity of soils had deleterious effects on all the parameters used. Addition of organic matter resulted in marked increases in bacterial counts, formazan production, and CO2 evolution. Glucose showed the most rapid effect and highest levels. Wheat straw yielded the highest results and sawdust always showed the least effect.

Evaluation of some biological tests as parameters for microbial activities in soils. II. Field investigations.

Investigations were designed to study the effect of certain factors on the microbial activities in soil. The parameters, used as an index of the microbial activities, were total bacterial counts, dehydrogenase activity, oxidation of organic carbon, and CO2 evolved/7 days. Bahteem Farm clay soil was examined for determining the effects of depth, type of fertilization, and crop rotation on the microbial activities. It appears that the microbial activities, as indicated by the tested parameters, were more pronounced in the surface 15 cm-layer than in the subsurface layer (15-30 cm). Results of all the parameters tested showed markedly higher increases with farmyard manure than with nitrogenous fertilizer and in the control, without significant differences between the latter two. Moreover, the time of sampling had no effect on the results obtained for all parameters. Different types of rotations did not exert significant variation in total bacterial counts, though more than one crop per year increased the organic carbon content of soil and mostly the dehydrogenase activity, whereas the evolution of CO2 tended to decrease. At Gabal el-Asfar Farm, the effect of irrigation with sewage effluent, for long periods, on the microbial activities of sandy soil was investigated. Sewage water stimulated the total bacteria, raised the dehydrogenase activity, the organic carbon, and the production of CO2. In North El Tahreer and Mariut Sectors, the effect of both the type and age of cultivation on the microbial activities in the calcareous soils were examined. Cultivation raised the figures of all the tested parameters progressively with time of cultivation. It was also noticed that crops exerted more beneficial effects on microbial activities than orchards, and the dehydrogenase test was the most reliable parameter to reveal this fact.

Biological activities during ripening of composts.

Three investigations were carried out. The first determined the relationships between dehydrogenase acitivty throughout the course of composting wheat straw and the changes in both organic carbon and total nitrogen. The second investigation tested the validity of the first investigation results. The third dealt with the effect of the degree of ripening of a compost, expressed by age and C/N ratio, on its dehydrogenase activity, and production of CO2. The results revealed continual decreases in the organic carbon, coincident with increases in total N and dehydrogenase activity. Noticeable chemical and biological changes occurred in the first and third month. Levels of dehydrogenase were highest in rice straw and lowest in cotton stalk compost, while the wheat straw compost occupied an intermediate position. Aging of the compost resulted in increases in the dehydrogenase figures and decreases in the amounts of CO2 produced.