Evaluation of surface irrigation as a function of water infiltration in cultivated soils in the Nile Delta

As sources of irrigation water are decreasing, efficient use of surface irrigation is essential. The purpose of this study is to determine if partially-wetted furrow irrigation has more efficient water storage and infiltration than traditional border irrigation in an alluvial clay soil under cultivated grape production. The two irrigation components considered were wet (WT) and dry (DT) treatments, at which water was applied when available soil water reached 65 % and 50 %, and the traditional border irrigation control. Empirical power form equations were obtained for measured advance and recession times along the furrow length during the irrigation stages of advance, storage, depletion and recession. Coefficient of variation (CV) was 5.2 and 9.5 % for WT and DT under furrow irrigation system comparing with 7.8 % in border, respectively. Water was deeply percolated as 11.9 and 19.2 % for wet and dry furrow treatments respectively, compared with 12.8 % for control, with no deficit in the irrigated area. Partially-wetted furrow irrigation had greater water-efficiency and grape yield than dry furrow and traditional border irrigation, where application efficiency achieved as 88.1 % for wet furrow irrigation that achieved high grape fruit yield (30.71 Mg /ha). The infiltration (cumulative depth, Z and rate, I) was functioned to opportunity time (t ₀ ) in minute for WT and DT treatments as: Z _WT ?=?0.528?t ₀ ^0.6, Z _DT ?=?1.2?t ₀ ^0.501, I _WT ?=?19?t ₀ ^?0.4, I _DT ?=?36?t ₀ ^?0.498. Empirical power form equations were obtained for measured advance and recession times along the furrow length during the irrigation stages of advance, storage, depletion and recession. The irrigation parameters and coefficients, and soil water distribution have been also evaluated.     

Mycobacterium marinum infection in fish and man: epidemiology,pathophysiology and management; a review

Mycobacterium marinum is an opportunistic pathogen inducing infection in fresh and marine water fish. This pathogen causes necrotizing granuloma like tuberculosis, morbidity and mortality in fish. The cell wall-associated lipid phthiocerol dimycocerosates, phenolic glycolipids and ESAT-6 secretion system 1 (ESX-1) are the conserved virulence determinant of the organism. Human infections with Mycobacterium marinum hypothetically are classified into four clinical categories (type I–type IV) and have been associated with the exposure of damaged skin to polluted water from fish pools or contacting objects contaminated with infected fish. Fish mycobacteriosis is clinically manifested and characterized in man by purple painless nodules, liable to develop into superficial crusting ulceration with scar formation. Early laboratory diagnosis of M. marinum including histopathology, culture and PCR is essential and critical as the clinical response to antibiotics requires months to be attained. The pathogenicity and virulence determinants of M. marinum need to be thoroughly and comprehensively investigated and understood. In spite of accumulating information on this pathogen, the different relevant data should be compared, connected and globally compiled. This article is reviewing the epidemiology, virulence factors, diagnosis and disease management in fish while casting light on the potential associated public health hazards.     

Prediction of optimal vaccination timing for infectious bursal disease based on chick weight

Growth rate in broiler birds has increased substantially in the last decade due to improvement in genetics, feed formulation, cleaner environment, and vaccine formulations. As a result, it has become necessary to review and revise prediction method for vaccination in chicks. This study was undertaken to determine the possible use of the rate of weight gain rather than age in predicting vaccination time. Two groups of 1-day-old broilers originating from old and young breeders, respectively, and with different levels of maternal antibodies against infectious bursal disease virus (IBDV) were used in this study. The chicks were divided into four groups and subjected to two feed regiments: groups A1 and B1 were fed broiler feed for normal growth rate, and groups A2 and B2 were fed breeder feed for slower growth rate. At 1, 4, 8, 12, 16, 22, 29, and 36 days of age, 22 chicks in each group were weighed, and blood samples were collected. Serum samples were tested for antibodies against IBDV by enzyme-linked immunosorbent assay (ELISA) and virus neutralization test. Maternal antibody decline curves for each group were plotted according to chick age and chick weight. Fast-growing birds in groups A1 and B1 showed a faster rate of antibody decline, whereas slow-growing birds in groups A2 and B2 had a slower rate of antibody decline. Based on the effect of weight gain on maternal antibody decline, a new way of predicting vaccination time for IBDV based on measuring maternal antibody titers at 4 days of age was proposed and tested. The predicted antibody decline was shown to correspond to the real ELISA titers measured in our experiments (R = 0.9889), whereas a lower correlation (R = 0.8355) was detected between real ELISA titers and the titers predicted by the current method using age-based Deventer formula.     

Pharmacokinetics of chloramphenicol in normal and Escherichia coli infected chickens

1. Disposition kinetics were compared in healthy chickens and in chickens naturally infected with E. coli following the intravenous, intramuscular and oral administration of chloramphenicol in a single dose of 20 mg/kg body weight. 2. Lower serum chloramphenicol concentration in diseased chickens were reported after intravenous injection, but they were higher than normal 30 min after intramuscular and oral administration. Following intravenous injection the volume of distribution was increased in diseased chickens. 3. The biological half-life in normal chickens was 8.32 +/- 0.5 h and was prolonged in diseased birds (26.21 +/- 0.2 h). The body clearance of chloramphenicol was reduced in diseased chickens. 4. The rate of absorption of chloramphenicol was delayed after administration via the oral route but the extent of absorption was increased. The maximum concentration was higher and it was reached after a longer time in diseased than in normal chickens after administration by both intramuscular and oral routes.     

Influence of E. coli infection on the disposition kinetic of nalidixic acid in broiler chickens.

The pharmacokinetic data of nalidixic acid were investigated in normal and E. coli infected chickens. The highest serum concentration were reached after 2 hours with t0.5 (ab) of (1.706 +/- 0.1 min in normal and 2.030 +/- 0.11 min in diseased) and (1.72 +/- 0.11 min in normal and 1.416 +/- 0.044 in diseased chickens) following oral and intramuscular administration, respectively. The elimination half-life t0.5 (beta) were (2.514 in normal and 2.35 hr in diseased) and (2.567 hr in normal and 2.672 hr in diseased) respectively. Following intravenous injection the kinetic of nalidixic acid followed two compartments open model with t0.5 of (6.27 and 9.15 hr), Vd (0.45 and 0.79 L/kg), Cltot (8.86 and 13.32 ml/kg/min) in normal and E. coli infected chickens, respectively. Administration of nalidixic acid twice daily for 5 successive days in a dose level of 25 mg/kg b. wt. by oral and intramuscular routes showed a cumulative behaviour.     

Biological activity of Thyme oil and Thymol againstTetranychus urticae Koch

Thyme oil was obtained by hydrodistillation and Thymol the major constituents was purchased from Prolabo Co. and they were tested againstTetranychus urticae Koch. Thymol was more potent than Thyme oil as a deterrent factor for reducing egg laying by the mite. Mortality percentage reached 100% with both materials used, however, with low concentration the effect was pronounced with Thymol than Thyme oil.     

Development of two species-specific primer sets to detect the cereal cyst nematodes Heterodera avenae and Heterodera filipjevi

Twelve Heterodera species are of major economic significance in wheat and barley. Of these, H. avenae, H. filipjevi and H. latipons are among the most important ones, and sometimes coexist. The identification of Heterodera species using morphological characteristics is time consuming, requires specialized skill and can be imprecise, especially when they occur mixed in field populations. Molecular techniques can provide a more accurate way for nematode identification. This study reports the results of experiments targeting the mitochondrial cytochrome oxidase subunit 1 (COI) gene to develop species-specific primers that could be used for the identification of H. avenae and H. filipjevi. The COI gene of 9 Heterodera spp. and Punctodera punctata was partially sequenced and the resultant sequences were aligned to find unique sites suitable for the design of primers. The alignment showed variability between H. avenae, H. filipjevi and other Heterodera species. Two sets of species-specific primers were identified for the identification of both species and the conditions for their use in PCR were optimised. The specificity of the designed primers was checked by comparison with one population of P. punctata and populations of 14 other Heterodera species, nine populations of H. avenae and 10 populations of H. filipjevi originating from different countries. To test the sensitivity, the PCR was run with DNA extracted from five second-stage juveniles (J2) of H. avenae or five J2 of H. filipjevi mixed with DNA extracted from varying numbers of J2 of H. latipons. It was possible to detect as few as five J2 of H. avenae or H. filipjevi among 100 J2 of H. latipons. The two primers sets allow the detection of H. avenae and H. filipjevi where they occur in mixed populations with other Heterodera spp.     

Electron microscopy of living insects

Electron micrographs of living specimens of the various developmental stages of the insect Tribolium confusum have been obtained with a scanning electron microscope. In most cases the specimens resumed their normal activity after being examined with the electron microscope and under went metamorphosis into the next stage.