Biological control of Meloidogyne incognita by Trichoderma harzianum and Serratia marcescens and their related enzymatic changes in tomato roots

Biological control against the root-knot nematode, Meloidogyne incognita was proven to occur in tomato, Solanum lycopersicom, soil-drenched with different isolates of Trichoderma harzianum and a commercial suspension of Serratia marcescens (Nemaless). The potential of such biocontrol agents to trigger plant defense response was discussed. Nematode reproduction in the presence of such possibly induced systemic resistance (ISR) elicitors was compared with that occurring on untreated plants and treated plants with the carbofuran nematicide. Dosages used were for carbofuran (1 mg ai/kg soil) and for S. marcescens (1 ~ 109 bacterium cells/ml water) 2 ml suspension/kg soil; three different T. harzianum isolates (f1, f3 and f8) were separately added at 50 ~ 10Sup>8 CFU/kg soil. The possible ISR elicitors were tested on two tomato cultivars (Super Strain B and Alisa), which were inoculated with active juveniles (J2) of M. incognita, and plants were kept in a glasshouse. Indices of plant fitness (PFs) resulting from each treatment, which took into account various growth parameters were also determined. Carbofuran followed by S. marcescens and T. harzianum significantly decreased (P . 0.05) nematode development and reproduction when compared with the untreated controls. PF of cv. Alisa was higher than that of Super Strain B, and M. incognita reproduced better on the latter cultivar in all treatments. Polyphenol oxidase (PPO) and β-1,3-glucanase (GLUC) activities were detected in the roots of inoculated and uninoculated control tomato plants. Similar tests were carried out on inoculated plants treated with such ISR elicitors to search for possible enzyme activity changes as a result of resistance induction. Nematode infection did not cause any significant changes in GLUC activity, whilst PPO activity was enhanced in inoculated with respect to uninoculated roots. Treatments with ISR elicitors and carbofuran did not significantly change GLUC activity in both inoculated plants and uninoculated controls. While in the presence of the ISR elicitors, generally, PPO activity did not increase as a result of nematode infestation.Key words: Enzymatic induction, root-knot nematode, nematode management, Serratia marcescens, Trichoderma harzianum, biological control, carbofuran, nematicide, polyphenol oxidase, β-1,3-glucanase, Solanum lycopersicum

Chronic hepatitis C in children: Clinical spectrum and histopathological study

Introduction: Hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver disease. An estimated 180 million people are infected worldwide. The prevalence of hepatitis C virus (HCV) infection is relatively low in children, with an anti-HCV prevalence rate of 0.2–0.4% in the Western world. Egypt has the highest prevalence of adult HCV infection in the world, averaging 15–25% in rural communities. The main (90%) HCV genotype is type 4. The magnitude of HCV infection in children is not well studied. Asymptomatic HCV infection is detectable in 2.02% of Egyptian children.Aim: To study the clinical presentation and histopathological features of the liver in children with chronic hepatitis C infection.Methods: The study population included 40 children from 2 to 16 years who had been diagnosed with chronic hepatitis C (HCV-RNA positive for 6 months or more by Real-time PCR) in the liver clinic at El-Shatby Children Hospital.Results: Among the 40 patients’ biopsies, 26 (65%) were stage 0, 10 (25%) were stage 1, 4 (10%) were stage 2–3 (HAI). The grades of all 40 children ranged between 0 and 1 (HAI). Developing fibrosis was significantly associated with age (P =0.015).Conclusion: Children with chronicHCV infection are generally asymptomatic. Significant hepatic fibrosis was present in 10%of children with HCV infection. Fibrosis stage was significantly higher in older age children. There was no significant association between fibrosis stage and any biochemical parameter.Keywords: Chronic hepatitis C; Children; Egypt; Clinical profile; Histopathologic change