Ten bacterial strains, selected from a bulk of isolates recovered from tomato rhizosphere, were tested for their ability to induce systemic resistance or bio-control agents against Meloidogyne incognita in tomato under greenhouse condition. Results showed that all ten tested bacterial strains showed significant reduction in nematode development and reproduction. The most effective strains were Methylomonas methanica, Bacillus cereus, Bacillus brevis and Obesumbacterium proteus. They were achieving the highest reduction in nematode total population and fecundity. Plant growth was improved as a result of application of rhizobacteria. Antioxidant enzymes activity for both peroxidase and polyphenol oxidase were elevated in bacteriazied plants compared nematode infected plant as well as total phenol content. Results revealed that crude culture suspension of bacteria was more effective for reducing nematode population followed by cell-free culture filtrates, bacterial live cells and bacterial dead cells suspension, sequentially. It was concluded that these bacteria able to suppress M. incognita as resistance inducers for tomato plants or bio-control agents.

The potency of the some chemicals from different groups known as inducers of systemic acquired resistance (SAR) viz., acetylsalicylic acid (ASA), DL-3aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA), 5-chlorosalicylic acid (CSA), nitrosalicylic acid (NSA),salicylic acid (SA),ascorbic acid (AS), and selenium (SE) in reducing reproduction Meloidogyne incognita in tomato plants cv. Castel rock was investigated under greenhouse conditions. Supplying chemicals three days-before nematode inoculation showed maximum efficacy in reducing nematode galls, egg-masses and eggs numbers followed by synchronized addition with inoculation, while post-inoculation treatment was less effective. Reiterative doses post-inoculation were improved the efficacy of single dose, also three doses used were more effective than one or two, while, differences between two or three doses were insignificant. On the other hand, plant fitness was slightly impaired with third dose than second one. INA and SE showed pronounced effect in inhibition nematode population after third dose compared with the rest chemicals, which showed mild increase in their efficacy from second to third doses. Unfortunately, three doses of SE were reduced plant fitness after enhanced by double doses, while INA was showed obvious phytotoxicity gradually increased by repeating doses. Gathering between the most effective application time (before inoculation) and the proper activated dose after inoculation was studies for emphasized their action and comparing with pre-inoculation only in suppressing M. incognita population. Chemical activators showed enhancing in peroxidase and polyphenoloxidase activities. In conclusion, CSA, NSA, BABA and SA were showed highest efficacy as resistance inducers. This collectively showed reduction of total population with pre-inoculation time application and pre plus post-inoculation application, 57.6&83.8%, 56.5&81.6%, 55.4&79.2% and 54.5&78.1%, respectively. Also the fecundity of nematode was taking similar trend as total population. The results suggest that tested chemicals especially CSA, NSA, BABA and SA have potential to suppress root-knot nematode infection in tomato plants through induced systemic resistance.

There is strong correlation between changes in abundance of specific bacterial species and several diseases including schistosomiasis. Several studies have described therapeutic effects of curcumin (CUR) which may arise from its regulative effects on intestinal microbiota. Thus, we examined the impact of CUR on the diversity of intestinal microbiota with/without infection by Schistosoma mansoni cercariae for 56 days. Enterobacteriaceae was dominating in a naive and S. mansoni infected mice group without CUR treatment, the most predominant species was Escherichia coli with relative density (R.D%) = 80.66% and the least one was Pseudomonas sp. (0.52%). The influence of CUR on murine microbiota composition was examined one week after oral administration of high (40) and low (20 mg/kg b.w.) CUR doses were administered three times, with two day intervals. CUR induced high variation in the Enterobacteriaceae family, characterized by a significant (p < 0.001) reduction in E. coli and asignificant (p < 0.001) increase in Pseudomonas sp. in both naïve and S. mansoni-infected mice, compared to untreated mice, in a dose-dependent manner. Additionally, our study showed the effects of high CUR doses on S. mansoni infection immunological and parasitological parameters. These data support CUR’s ability to promote Pseudomonas sp. known to produce schistosomicidal toxins and offset the sequelae of murine schistosomiasis.

http://eajbsf.journals.ekb.eg/ Comparison between the Effectiveness of Certain Insecticides and Entomopathogenic Nematodes Against Tortoise Beetle, Cassida vittata (Vill.