The adverse effects of sea water salinity on number of nodules, nitrogen content, nitroginase activity, Chlorophyll a and b content, proline accumulation and protein pattern of faba bean plants (Vicia faba commercial cultivar Nubaria 1) were investigated. Faba bean plants were irrigated with sea water at 20, 25, 30, 40 and 50% concentrations and inoculated with rhizobial isolate ARC307 or with gamma rays treated isolates namely; ARC1, ARC2, ARC3, ARC4, ARC5, ARC6 and ARC7. Nodules number, nitrogen content, nitroginase activity and chlorophyll a and b content parameters were decreased by increasing sea water salinity with all used isolates, while proline accumulation parameter increased. At the same time, ARC2 isolate showed the highest values for these parameters above all isolates including the parental isolate ARC307 at all studied concentrations except for proline accumulation parameter, it was the least. Therefore, ARC2 considered as a promising isolate for salt tolerance. Salinity enhanced the occurrence of particular novel proteins in faba bean plants infected with ARC2 isolate.

J o u rn al of M ic ro b ia l & Bioc h e m ic a l Te chno lo g y

No abstract

orf256 is a wheat mitochondrial gene associated with cytoplasmic male sterility (CMS) that has different organization in various species. This study exploited the orf256 gene as a mitochondrial DNA marker to study the genetic fingerprint of Triticum and Aegilops species. PCR followed by sequencing of common parts of the orf256 gene were employed to determine the fingerprint and molecular evolution of Triticum and Aegilops species. Although many primer pairs were used, two pairs of orf256 specific primers (5:-94/C: 482, 5:253/C: 482), amplified DNA fragments of 576 bp and 230 bp respectively in all species were tested. A common 500 bp of nine species of Triticum and Aegilops were aligned and showed consistent results with that obtained from other similar chloroplast or nuclear genes. Base alignment showed that there were various numbers of base substitutions in all species compared to S. cereal (Sc) (the outgroup species). Phylogenetic relationship revealed similar locations and proximity on phylogenetic trees established using plastid and nuclear genes. The results of this study open a good route to use unknown function genes of mitochondria in studying the molecular relationships and evolution of wheat and complex plant genomes.

Avermectins are a complex of chemically related naturally occurring macrocyclic lactones which first isolated as a natural fermentation product of a soil actinomycete, Streptomyces avermitilis, in 1976 (Burg et al. 1979). The naturally occurring avermectins can be separated into four homologous pairs, of which one, abamectin (avermectin B1), which consists of 80% of avermectin B1a and 20% of avermectin B1b has been developed for use against arthropod pests of horticulture and agronomic crops (Dybas and Green 1984). Currently, it is rapidly worldwide growing in usage for many agronomic crops. They are potent chemotherapeutic agents against animal parasitic nematodes and many veterinary and agricultural arthropod pests (Putter et al. 1981, Campbell et al. 1983, Lasota and Dybas 1991). Abamectin increases calcium permeability to chloride ions, which is independent of the neurotransmitter, gamma aminobutyric acid (GABA)-mediated chloride ion channels (Calcott and Fatig 1984). The compounds' mechanism of toxicity in mammals is unknown but GABA is a mammalian central nervous system neurotransmitter and effects on GABA may be relevant to their safety in mammals (Lankas and Gordon 1989). Carcinogenicity studies with abamectin at maximum tolerated dosage levels for 22 and 24 months duration in mice and rats, respectively, have demonstrated the lack of carcinogenicity of this compound (Lanks and Gordon 1989). Also they showed the lack of genotoxic activity of abamectin in a variety of assays. Abamectin degradates were tested and found to have no adverse maternal and developmental effects in CF 1 mouse, the laboratory species/strain most sensitive to abamectin toxicity. In addition, the degradates from photolysis of thin films were negative in the microbial mutogenesis assay (Crouch et al. 1992). The specific objectives of the present study were; (1) to estimate the percentage of mitotic abnormalities in male mice bone marrow cells induced by abamectin and its degradates, (2) to measure the amount of spermhead abnormalities in male mice caused by abamectin. Materials and methods Chemical Commercially available sample of abamectin, as 'Avermectin B1', 1.8% wt/vol emulsifiable concentrate, produced by Merck, Sharp & Dohme, Three Bridge, N. J., USA., was used in the bioassays. The chemical structure is a mixture of homologous products with a minimum of 80% B1a and a maximum of 20% B1b components. The B1b component differs chemically from the B1a component by only 1 methylene (CH2) unit at the 26-carbon position; the ethyl group (C2H5) is a methyl group in the B1b form. The compound's dilutions were made in distilled water.