The response of Musca domestica (L.) in farms sprayed for long periods by organochlorine to synthetic pyrethroids.

Resistance ratios for Musca domestica collected from animal farms and poultry units, sprayed by organochlorine insecticides for long periods and standard laboratory strain were determined. The data indicated high significant resistance in animal farms population to organochlorine compounds and cross-resistance to synthetic pyrethroids. The organochlorine resistant and standard laboratory strains were examined for knockdown and rate of penetration to two synthetic pyrethroids. Standard laboratory strain was knocked down within few minutes by lower or higher dosages. Resistant strain was unaffected by lower dosages within 24 hours and partly by higher dosages. Penetration was faster in the resistant than in the standard strain. However, significant differences did not occur until after the standard laboratory females become moribund. The higher penetration rate in the resistant housefly adults was attributed to their continued activity throughout the exposure periods.

Rodenticidal activity of two natural coumarines from ether extract of Citrus bergamia.

The rodenticidal activity, expressed by LD50 values of ether and petroleum ether extracts of Citrus bergamina pulp against two rat species, Rattus norvegicus (Norway rat) and Rattus rattus (roof rat) was evaluated. Based on LD50 values, ether extract was nearly 1.6 and 1.3 times more toxic to Norway rat and roof rat than ethanol respectively, while pet. ether extract was non toxic to the two rat species. From ether extract, two natural coumarines, Bergapten and Coumurrayin were isolated and tried against the two rat species as anticoagulant rodenticides. Norway rats were more susceptible to both compounds than the roof ones. A direct parallel relationship was found between the toxicity and changes in the blood picture.

Studies on the phytoplankton populations and physico-chemical conditions of treated sewage discharged into Lake Manzala in Egypt.

Over a full year, the phytoplankton populations and physico-chemical conditions of treated sewage discharged into Lake Manzala in Egypt were investigated. Sixty-seven species of algae were identified, 18 Cyanophyta (Cyanobacteria), 19 Chlorophyta, 21 Bacillariophyta, 6 Euglenophyta, 2 Cryptophyta and one species Pyrrhophyta. Nitzschia (6 spp.), Scenedesmus (6 spp.), Navicula (4 spp.), Oscillatoria (4 spp.) and Euglena (4 spp.) were the most common genera. A remarkable seasonal variation in species composition and standing crop of the phytoplankton populations was noted during the study. The total phytoplankton standing crop appeared to be mainly dependent on the growth of certain species viz., Oscillatoria chalybea, O. princepes, O. tenuis, Microcystis aeruginosa, Anabaena constricta (Cyanophyta), Nitzschia obtusa, Bacillaria paradoxa, Cocconeis placentula, Cyclotella meneghiniana (Bacillariophyta), Pandorina morum, Volvox sp. (Chlorophyta) and Phacus curvicauda (Euglenophyta). The continuous presence of Anabaena constricta and Nitzschia palea was recorded in the treated sewage. The least represented algal divisions were Pyrrhophyta and Cryptophyta, both in terms of quality and quantity. The data indicate that the secondary effluents were unstable in their chemical features and grossly polluted. Therefore, the treatment systems must treat the discharged sewage to a tertiary level before discharging into Lake Manzala.

Effect of treated sewage on the water quality and phytoplankton populations of Lake Manzala (Egypt) with emphasis on biological assessment of water quality.

The effect of treated sewage on the quality of water and phytoplankton populations of Lake Manzala was studied with emphasis on use of algae to monitor water pollution as part of a search for a biological assessment of water quality. Lake Manzala is situated at the northern part of the Nile-delta, Egypt. Disposal of treated sewage into Lake Manzala appeared to have differential effects on water quality and phytoplankton populations. Marked seasonal and local variations were observed for the physical and chemical characteristics of water. 157 species of algae were identified, 59 Chlorophyta, 37 Bacillariophyta, 30 Cyanophyta (Cyanobacteria), 28 Euglenophyta, one Pyrrhophyta and 2 Cryptophyta. Distribution and abundance of these algal divisions were found to differ at different sampling stations. Qualitative and quantitative growth of each algal division displayed great seasonal variations. The phytoplankton standing crop was mainly due to the contribution of Bacillariophyta whereas the species composition is dependent mainly on Chlorophyta. A great parallelism was noted between the quality of water samples based upon the chemical and physical investigations and their quality based upon the biological indices. Compound eutrophication index indicated that the nature of the investigated water ranged between eutrophic and hypereutrophic conditions. Diversity index values indicated that the water in the study area was of a moderate level of pollution. Saprobic index and saprobic quotient revealed the presence of beta- to alpha-mesosaprobic forms of algae.

Anomalous origins of colic arteries.

The topography of the celiac trunk and superior and inferior mesenteric arteries was studied by dissection in 27 embalmed cadavers. Variant vascular patterns were noted in four subjects. These consisted of: (1) an accessory right hepatic artery from the superior mesenteric artery, (2) an anomalous middle colic artery from the proximal segment of the splenic artery, and (3) two instances of an accessory left colic artery originating from the superior mesenteric artery. The precarious course of the middle colic artery (coming from the splenic artery) and its dominance in the formation of the marginal artery were thought to predispose the ascending and transverse colon to an increased risk of vascular damage. These cases also illustrate two variant patterns of formation of the marginal artery. In the case of the anomalous middle colic artery, the only contribution of the superior mesenteric artery to the marginal artery was through the anastomosis of its ileocolic branch with the right branch of the aberrant middle colic artery. In subjects with accessory left colic arteries, the superior mesenteric artery played a dominant role in the formation of the marginal artery by contributing the accessory left colic artery, which supplied the splenic flexure and the proximal part of the descending colon. These arterial variations underscore the importance of doing vascular studies prior to major abdominal surgery.

Toxicity of colocynithin and hydrated colocynithin from alcoholic extract of Citrullus colocynthis pulp.

The comparative toxicity of the alcoholic extract of Citrullus colocynthis pulp; colocynithin and hydrated colocynithin have been isolated and tried against seven insect species. The American cockroaches were more susceptible for both compounds than the German one, adult honey bee were more affected with Colocynithin than adult housefly. while hydrated colocynithin was more toxic to housefly than honey bee, cotton leafworm was less affected with both toxicants. Bed bug was less affected with Colocynithin than mosquito, but V.V. with hydrated Colocynithin. A direct parallel relation was found between toxicity and rate of penetration.