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THIS STUDY aimed to evaluate the efficacy of applying spores and chitinase enzyme of Streptomyces parvulus strain 10d in biological control of damping-off disease caused by Rhizoctonia solani in green beans (Phaseulus vulgaris) and compare it with Rhizolex fungicide application. Five seeds of green bean were sown in plastic pots, filled with either sterilized or non-sterilized soils, infested with R. solani inoculum (5g/kg soil). Pots were kept in the greenhouse for 45 days from sowing. Pre-emergence damping-off was recorded 15 day from planting and post-emergence damping-off and survival rate were recorded 30 days from planting. Plants growth characteristics were recorded 45 days of sowing.Results showed that Rhizolex treatment had the best survival rate and lowest root–rot severity (79 and 25%), followed by crude enzyme treatment (76 and 25%), then spores’ treatment (75 and 27%, respectively), in infested and non-sterilized soils.For plant growth characteristics, in infested and non-sterilized soil, spores’ treatment had the best effect on plant height (41.5cm), followed by crude enzyme (39.5cm) and Rhizolex treatments (34.6cm). Numbers of leaves/plant were the highest in Rhizolex (17), followed by spores (15) and enzyme treatments (14). Numbers of pods/plant were 14 in Rhizolex treatment and 11 in crude enzyme and spores’ treatments. The highest dry weight was recorded in spores’ treatment followed by Rhizolex treatment (10 and 7 g/plant, respectively). Conclusions: results suggest that using chitinolytic Streptomyces strain 10d for the biological control of R. salani and damping-off disease of green bean plants can be an attractive alternative for pesticides in organic agriculture.

Parasitic isopods have received considerable attention as they cause series impacts on their hosts either alone or with other environmental stresses such as water pollution. The present study investigated the infestation status with isopods among the fry collected from the natural sources .Also to demonstrate the effects of different salinity and temperature combination on the survival rates of the identified isopods under the laboratory conditions. In March 2017,a total of 16 thousand mugiliid fry were sampled from The Fry Collection center at Al Behera Governorate ,Egypt and examined for the presence of isopods .Samples were found infested with a rate of 10.6% , the result which practically documented that isopods were introduced into lake Qarun through dumping millions of infected fry from this source without biosecurity procedures. The isolated juvenile isopods were morphologically and molecularly identified as Livoneca redmanii species by using 16S rRNA gene and recorded in the GenBank with accession number: MK584629. The effects of variables of salinity/ temperature combination on the survival% of the identified juveniles showed that the best survival rate(100%) was recorded in salinity 15 -20% at temperature 25⁰C while the lethal combination was in salinity 10, 20,50 and 60% at temperature 35⁰C . Statistical analysis using A-two way ANOVA indicated a significant interaction between the effect of different degree of temperature and variance of salinity% on the survival of L. redmanii juveniles. Analysis of one way ANOVA indicated that the most effective temperature of overall mean temperature affected on survival of juvenile stage was 35 C⁰ while the most effective salinity percentage on survival of Juvenile from overall mean of salinity % was 10%. Results of this study provided applicable procedures which can be recommended as a precaution measures and for eliminating the isopod juvenile stages among the mugiliid fry.

Cholera is a negative public health event caused by Vibrio cholerae. Although V. cholerae is abundant in natural environments, its pattern and transmission between different niches remain puzzling and interrelated. Our study aimed to investigate the occurrence of nonpathogenic V. cholerae in the natural environment during endemicity periods. It also aimed to highlight the role of molecular ecoepidemiology in mapping the routes of spread, transmission, and prevention of possible future cholera outbreaks. V. cholerae was detected in different aquatic environments, waterfowl, and poultry farms located along the length of the Nile River in Giza, Cairo, and Delta provinces, Egypt. After polymerase chain reaction amplification of the specific target outer membrane gene (Omp W) of suspected isolates, we performed sequence analysis, eventually using phylogenetic tree analysis to illustrate the possible epidemiological relationships between different sequences. Data revealed a significant variation in the physicochemical conditions of the examined Nile districts related to temporal, spatial, and anthropogenic activities. Moreover, data showed an evident association between V. cholerae and the clinically diseased Synodontis schall fish. We found that the environmental distress triggered by the salinity shift and elevated temperature in the Middle Delta of the Nile River affects the pathogenesis of V. cholerae, in addition to the characteristics of fish host inhabiting the Rosetta Branch at Kafr El-Zayat, El-Gharbia province, Egypt. In addition, we noted a significant relationship between V. cholerae and poultry sources that feed on the Nile dikes close to the examined districts. Sequence analysis revealed clustering of the waterfowl and broiler chicken isolates with human and aquatic isolated sequences retrieved from the GenBank databases. From the obtained data, we hypothesized that waterfowl act as a potential vector for the intermediate transmission of cholera. Therefore, continuous monitoring of Nile water quality and mitigation of Nile River pollution, in addition to following good managemental practices (GMPs), general hygienic guidelines, and biosecurity in the field of animal production and industry, might be the way to break this cyclic transmission between human, aquatic, and animal sectors.

Skin wounds are the most prevalent daily affections intruding fishes in an aquaculture facility. Such skin affections are considered to be the most common portals of entry for disease agents affecting fishes. This persistent phenomenon necessitates a comprehensive search for an efficient healing therapy to combat the ongoing dermal damage and its pathological consequences. In the current study, the core hypothesis has been vigorously tested through the experimental application of hemodialysate (Solcoseryl®) solution in several exposure methods including bath, intraperitoneal (I.P.), intramuscular (I.M.), and local infiltration routes. All tested routes were capable of inducing different degrees of healing in Nile tilapia (Oreochromis niloticus). The core hypothesis of the current research has been experimentally accomplished through assessing the resultant healing degrees based on both gross as well as tissue alteration dynamics among total of 5 experimental groups. Each group consisted of 10 fishes/aquarium. The swift tissue healing of the induced wounds in Nile tilapia were completely achieved 4 days post I.M. injection of the Solcoseryl® solution (10 μl/50 g fish as a single dose) with an excellent healing grade (+++++). However, bath treatment (1 ml/Lwater as a single dose) and local infiltration (10 μl/50 g fish as a single dose) have proved to be second on the race (complete healing was achieved 6 days post treatment with very good grade (+++)). This study demonstrates the clinical value of fish models in establishment of new approach for combating prevalent invasive skin affections in aquaculture.

Mass mortalities of angelfish eggs accompanied with very low hatchability were reported in a private ornamental fish farm in Egypt. Examined eggs were badly damaged by water mould that was decisively confirmed as Saprolegnia species. Presumptive identification of the ten retrieved isolates was initially suggestive of Saprolegnia species. Mycological investigations have revealed that only 7 out of 10 isolates were capable of producing sexual stages. Therefore, using molecular tools such as PCR coupled with partial sequencing of inter-transcribed spacer (ITS) gene was one of the most important approaches to distinguish Saprolegnia parasitica from other water moulds. The sequences of ITS gene data derived from eight isolates showed 100% similarity with S. parasitica ATCC90312 sequence and the remaining two isolates were different in one nucleotide (99.9%). The phylogenetic analysis of ITS genes grouped the ten isolates with other S. parasitica in one clad. Further, to control such fungal infection, the efficacy of povidone iodine as surface disinfectant for angelfish and their fertilized eggs were tested. By trial, it was obvious that the obtained post-rinsing results were highly suggestive for the efficacy of povidone iodine as an efficient antifungal disinfectant for both fish and eggs.

Fish, pathogen and environment are three counterparts who are sharing the same circle of life. To keep fish up to their optimal health, environment should be competently improved and pathogen count/virulence should be seized. Using of bioactive immunostimulants to achieve these objectives is the hypothesis under assessment. Thus, the present study was performed to evaluate the use of shrimp shells derived chitosan as an immunostimulant as well as preventive regime against Aeromonas hydrophila infection of Nile tilapia and to assess its antibacterial/aquatic bio-remediating effects. Results achieved by feeding 1% chitosan as preventive/therapeutic regimes have revealed a remarkably enhanced several innate immunological parameters (e.g., Phagocytic activity/index, NBT, Lysozyme activity and ACH50), increased resistance against A. hydrophila and strikingly improved water quality compared to the 0.5 and 2% chitosan containing diets. Conclusively, experimental results suggest the commercial usage of chitosan as an efficient immunostimulant and bio-remediating agent in aquaculture.

The objective of this research was to evaluate the safety of the 6/85 strain vaccine strain of Mycoplasma gallisepticum in turkeys by backpassing the vaccine strain up to 10 times by contact infection in turkeys and challenging turkeys with the resulting backpassaged strain. The vaccine strain, however, did not spread to in-contact turkeys, and it was necessary to reisolate the organism before challenging turkeys for the next passage. The challenge strain, therefore, was one that had been backpassaged four times in turkeys, with a total in vivo time in turkeys of 66 days. The backpassaged 6/85 vaccine strain was no different in pathogenicity than the original vaccine strain, except that at 10 days postchallenge, it was isolated in higher numbers from air sacs. Both the original 6/85 vaccine strain and the backpassaged strain were apathogenic in turkeys, except for a slightly increased diameter of the tracheal mucosa at 10 days postchallenge; at 20 days postchallenge the tracheal mucosal thickness was no different from that of controls.

Pathogenic Candida albicans was isolated from water and fish samples collected during an emergent event of mass mortalities among the juvenile Nile tilapia (Oreochromis niloticus), Sharp toothed catfish (Clarias gariepinus) along the stream of Mariotteya drainage. Investigations indicated that fish mortalities were confined to the area of Shubramant and Aboul Noumros (North to Sakara 7 drainage). C. albicans was isolated from the lesions associated with multiple skin ulcers in both Nile tilapia juveniles and Sharp toothed catfish. Assessment of the field and laboratory data has indicated that Mariotteya environmental disaster was a multifactorial problem. The fish mass kills were initially flared up through the dumping of the improperly treated nasty organic and inorganic chemicals from Elhawamdia sugar factory and municipal sewage. The physical stagnation of the stream, high levels of ammonia, phenol and polycyclic aromatic hydrocarbons (PAHs) and low levels of dissolved oxygen (DO) were all incriminated as the initial stimulus behind biological invasion of pathogenic bacteria (Pseudomonas fluorescence) and yeast (C. albicans). Pathologically, fishes were dying from both respiratory and osmoregulatory failure induced by the severe damage of both gills and skin. It has been implied that such environmental pollutants have direct damaging effects on gills, skin and fins with consequent suppression of the skin’s natural innate components. The adversely confronted immunological barriers were further exacerbated by the possible synergistic interactions of P. fluorescence dermotropic toxins followed by the secondary invasion of the pathogenic C. albicans.

Flavobacterium columnare (F. columnare), the dermotropic Gram negative yellow pigmented bacteria was isolated from different sites of skin ulcerations in the Nile tilapia (Oreochromis niloticus) and Nile catfish (Clarias gariepinus) collected from an earthen pond located at an aquaculture station in Sharkiya Province, Lower Egypt during an acute episode of mass kills during the early summer of 2009. An acute infection with F. columnare was behind the emergent event of mass mortalities among both populations. Many of the Nile tilapias exhibited typical signs of hole - in- the head like lesions from which F. columnare together with the myxosporean spore, Myxobolus tilapiae (M. tilapiae) were retrieved. Most of the cohabitating infected Nile catfishes exhibited severe form of saddle back like ulcer. The identities of the retrieved isolates were confirmed using morphological, biochemical and molecular tools. The research lead us to conclude that the two diverse etiological agents (F. columnare and M. tilapiae) under the triggering effect of the abrupt change in the water quality measures (abrupt rise in the water temperature, ammonia, pH, sharp decrease in dissolved oxygen) have synergized together to induce the above mentioned pathology with the consequent reemergence of fish mass mortalities.

A field visit was conducted in March 2002 to identify viruses infecting the faba bean ( Vicia faba ) crop in four governorates (Fayoum, Beni Suef, El-Nobareia and Bihera) in Egypt. A total of 71 faba bean samples with symptoms of viral infection (leaf rolling, yellowing and mosaic) were collected. These were tested at the Virology Laboratory of ICARDA, Syria, for seven viruses using the tissue-blot immunoassay procedure (Makkouk & Comeau, 1994). Specific rabbit polyclonal antisera were used to test for Chickpea chlorotic dwarf virus (CpCDV, genus Mastrevirus , family Geminiviridae ; provided by H. J. Vetten, BBA, Braunschweig, Germany); for Broad bean stain virus (BBSV, genus Comovirus , family Comoviridae ); for Bean yellow mosaic virus (BYMV, genus Potyvirus , family Potyviridae ) and for Pea seed borne mosaic virus (PSbMV, genus Potyvirus , family Potyviridae ). In addition, three specific monoclonal antibodies were used to detect Faba bean necrotic yellows virus (FBNYV, genus Nanovirus , family Nanoviridae ) (Franz et al ., 1996); Bean leaf roll virus (BLRV, family Luteoviridae ) (4B10; Katul, 1992) and Beet western yellows virus (BWYV, genus Polerovirus , family Luteoviridae ) (ATCC PVAS-647; American Type Culture Collection, Manassas, VA, USA). Serological tests showed that BYMV, an aphid-transmitted and seedborne virus that was identified in 89% of samples tested, was the most common virus. In most of the fields surveyed, BYMV symptoms were noted to occur at high levels (80–100% infection). PSbMV was detected in nine samples (one from Fayoum and eight from Beni Suef); FBNYV was detected in 11 samples (all from Beni Suef). CpCDV, a leafhopper-transmitted virus, was, by contrast, detected in only two samples collected from the El-Nobareia governorate showing leaf rolling, yellowing and stunting. BWYV, BLRV and BBSV were not detected in any of the samples tested. In Egypt, FBNYV, BYMV and PSbMV have previously been reported in faba bean (Makkouk et al ., 1994), but this is the first record of CpCDV affecting faba bean in Egypt. CpCDV is the only member of the Geminivirus that is reported to naturally infect faba bean.

The effect of urea additions on the microbiological and chemical properties of silage, produced from young maize plants (Darawa stage), was studied. Urea treatments, i.e., 0.25%, 0.50%, 0.75%, and 1.00%, stimulated higher densities of the desired microorganisms than the control, while undesired organisms showed lower counts (proteolytic and saccharolytic anaerobes). Addition of 0.25 to 0.50% or urea resulted in the production of high quality silage with pleasant small and high nutritive value, as confirmed by the various microbiological and chemical analyses conducted. Higher levels (0.75 and 1.00%) of urea decreased the quality of the product.

The effect of the herbicide atrazine on Fusarium oxysporum f. fabae and Rhizoctonia solani, the causative agents of wilt and rot, respectively, as well as rhizosphere microflora of broad bean plants was studied. The herbicide was applied at intervals of 30, 20, 10, and 0 days before sowing. Atrazine application reduced both densities and per cent of infection of these two pathogenic fungi, R. solani, however, was sensitive to atrazine itself, while F. oxysporum was affected by atrazine by-products. Rhizosphere flora, i.e., total microbial flora, actinomycetes, phosphate-dissolving bacteria, and fungal flora, were not affected by atrazine, but were deleteriously reduced by its by-products at early stages of plant growth. However, rhizosphere flora attained the normal levels after atrazine by-products had completely disappeared from soil (1 month after application), except for actinomycetes. Therefore, it is recommended to apply atrazine within 20 days before sowing for weed control as well as for controlling wilt and root rot infestations.

Summary The effect of the fungicide Dithan A-40 and the insecticide Cyolane on rhizosphere and soil microflora of broad bean plants cultivated in artificially infested soil with Fusarium oxysporum f. fabae was studied. F. oxysporum inoculation depressed the total microbial flora, actinomycetes and phosphate dissolvers while stimulated total fungi and Fusarium spp. in rhizosphere and soil. Application of Dithan A-40 or Cyolane, in general, stimulated different microbial groups except for total fungi and Fusarium spp. However, stimulation was more obvious in Cyolane treatment. Fungal spectra, in turn, showed a considerable sxift in pesticides treatments. Moreover, wilt incidence was significantly reduced in post-emergence infections, especially in Dithan A-40 treatment.

Summary The effect of the organophosphorus insecticide Nuvacron or Dipterex on rhizospherie microflora of broad bean plants infested with Fusarium oxysporum f. fabae or Rhizoctonia solani, wilt and root rot fungi, respectively, was studied. Moreover, influence of these insecticides on wilt and root rot incidence was also included. Soil inoculation with both phytopathogenic fungi proved inhibitory of normal rhizospherie flora. Nuvacron or Dipterex at the two levels applied, initially depressed densities of normal microflora, then counts progressively increased thereafter. The only exception was noted for phosphate dissolvers which showed a vast increase, indicating their activities in the mineralization of these organophosphorus insecticides. Despite the activity of insecticides applied in depressing the densities of Fusarium and Rhizoctonia spp. in rhizosphere only Nuvacron at the levels applied proved being effective in the control of wilt incidence. Unexpectedly, both insecticides significantly increased the spread of root rot disease. It is, therefore, recommended to apply Nuvacron not only for insect control, but also for achieving economic levels of wilt control.

140 soil samples from the Assiut governorate were examined for pathogenic fungi and actinomycetes. The paraffin-bait technique and a modified sodium citrate-utilizing procedure were used for recovery of Nocardia strains. Five isolations of N. brasiliensis were made by the sodium citrate method while 3 isolates were obtained by the other method. N. gypsoides was isolated for the first time, only the the modified method. It appears that the latter method suppresses to a great extent the growth of saprophytic fungi, hence increasing the possibility of the isolation of Nocardia spp. The effect of keratin enrichment on the isolation of dermatophytes from soil by the hair-bait technique was also investigated. Pretreatment of samples with dog hair or feathers increased the yield of isolates of Microsporum gypseum, Trichophyton terrestre and to a lesser extent, T. mentagrophytes, M. canis was recovered from soil only after its enrichment with dog hair. It is suggested that enrichment with other forms of keratinous material, either separately or in combination, might increase the recovery of keratinophilic fungi from soil.

Summary The effect of different concentrations of Dithan A-40 fungicide on the metabolic activities of the wilt fungus Fusarium oxysporum f. fabae and the root rot agent Rhizoctonia solani was studied. All toxicant concentrations reduced energy generation, total phosphorus and nitrogen content of both fungi. In addition, the toxicant caused a shift in free amino acids pool. As a result of these changes, the mycelium dry weight of both fungi was greatly reduced. R. solani was more sensitive to the toxic effect of Dithan A-40 than F. oxysporum .