A new homologous series of thermally stable thermotropic liquid crystalline poly(arylidene-ether)s based on 4-tertiary-butyl-cyclohexanone moiety was synthesised by solution polycondensation of 4,4 -diformyl- α , ω -diphenoxyalkanes, I a–f ,or4,4 -diformyl-2,2 -dimethoxy- α , ω -diphenoxyalkanes, II a–f , with the 4-tertiary-butyl-cyclohexanone monomer. A model compound III was synthesised from the monomer with benzaldehyde and characterised by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range of 0.18–0.92 dL/g. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by differential scanning calorimetry (DSC) and optical polarising microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermal properties of those polymers were evaluated by thermogravimetric analysis and DSC measurements and correlated to their structural units. X-ray analysis showed that polymers having some degree of crystallinity in the region 2 θ = 5–60 ◦ . In addition, the morphological properties of selected examples were tested by scanning electron microscopy.

Abstract Out of 210 actinomycetes isolates belonged to the genus Streptomyces recovered from rhizospheric soil of Triticum vulgaris, Zea mays and Vicia faba cultivated in Assuit and New Valley Governorates of Egypt, ten isolates were capable of producing high amounts of L-glutaminase enzyme. The most potent L-glutaminase producer isolate was Streptomyces sp. ASU319 recovered from rhizosphere of Triticum vulgaris. The higher producer actinomycete isolate was identified by sequencing of 16S rRNA as Streptomyces variabilis ASU319 and was deposited in the GenBank nucleotide sequence database under accession number KC145278. Factors affecting L-glutaminase production by the Streptomyces variabilis ASU319(KC145278) were examined and the results revealed that the maximum L-glutaminase value was obtained when the isolate cultivated in the production broth medium supplemented by glutamine 8 mg/ml, adjusted at pH 4 and incubated at 35 °C. These results suggest that L-glutaminase-producing Streptomyces variabilis ASU319 could be used as a plant growth promoting rhizobacteria by increasing the ammonia content in the rhizosphere soil across degradation of the agricultural wastes. Also this isolate can be used in both pharmaceutical and food industrial application for L-glutaminase production on commercial scale.

The present work focuses on the evaluation of the groundwater quality by chemical and bacteriological analyses to ensure its suitability for drinking and irrigation. Twenty groundwater samples were collected and analyzed from Manfalut district, Assiut, Egypt. Several water quality parameters were determined; the results show higher concentration of total dissolved solids (50 %), electrical conductivity (55 %), chloride (20 %), total hardness (20 %), and bicarbonate (55 %). This indicates signs of deterioration regarding drinking and domestic uses. Salinity hazard, sodium absorption ratio, sodium (Na) percentage, and residual Na carbonate were used to evaluate groundwater quality for irrigation. The values of electrical conductivity and SAR of groundwater samples were estimated illustrating that the most dominant classes are C2S1 (45 %; medium-salinity-low SAR), C3S1 (50 %; high-salinity-low SAR), and C4S1 (5 %; very high-salinity-low SAR). Bacteriological analysiswas also conducted for 20 groundwater wells from December 2011 to May 2012. Seven samples (35 %) are contaminated by bacteria (total and fecal coliforms); these wells are not suitable for drinking. The analysis exhibits that bacterial contamination was the maximum in wells located at the center of the study area; this may be due to using the residential septic tanks. It was also discovered that the quality of groundwater is suitable for irrigation in the target aquifer except in a few locations. As for drinking, about 55 % of the samples are not suitable. However, the groundwater wells which are located in the center of the study area are suitable for drinking according to the hydochemical analysis. It was found that some of these wells are not suitable based on bacteriological analysis.

Rhizobia-legume symbiosis depends on molecular dialog, which involves the production of specific plant flavonoid compounds as signal molecules. Rhizobium tibeticum was recovered from the root nodule of fenugreek and identified by sequencing the 16S rRNA gene. The effect of salinity stress on nod gene expression was measured in terms of b-galactosidase activity. R. tibeticum containing Escherichia coli lacZ gene fusions to specific nodulation (nod) genes were used to determine b-galactosidase activity. Combination of hesperetin (7.5 mM) and apigenin (7.5 mM) significantly increased b-galactosidase activity more than the single application of hesperetin or apigenin. Preincubation of R. tibeticum with hesperetin and apigenin combination significantly alleviates the adverse effect of salinity on nod gene expression and therefore, enhances nodulation and nitrogen fixation of fenugreek.

Rhizobia-legume symbiosis depends on molecular dialog, which involves the production of specific plant flavonoid compounds as signal molecules. Rhizobium tibeticum was recovered from the root nodule of fenugreek and identified by sequencing the 16S rRNA gene. The effect of salinity stress on nod gene expression was measured in terms of b-galactosidase activity. R. tibeticum containing Escherichia coli lacZ gene fusions to specific nodulation (nod) genes were used to determine b-galactosidase activity. Combination of hesperetin (7.5 mM) and apigenin (7.5 mM) significantly increased b-galactosidase activity more than the single application of hesperetin or apigenin. Preincubation of R. tibeticum with hesperetin and apigenin combination significantly alleviates the adverse effect of salinity on nod gene expression and therefore, enhances nodulation and nitrogen fixation of fenugreek.

Rhizobia-legume symbiosis depends on molecular dialog, which involves the production of specific plant flavonoid compounds as signal molecules. Rhizobium tibeticum was recovered from the root nodule of fenugreek and identified by sequencing the 16S rRNA gene. The effect of salinity stress on nod gene expression was measured in terms of b-galactosidase activity. R. tibeticum containing Escherichia coli lacZ gene fusions to specific nodulation (nod) genes were used to determine b-galactosidase activity. Combination of hesperetin (7.5 mM) and apigenin (7.5 mM) significantly increased b-galactosidase activity more than the single application of hesperetin or apigenin. Preincubation of R. tibeticum with hesperetin and apigenin combination significantly alleviates the adverse effect of salinity on nod gene expression and therefore, enhances nodulation and nitrogen fixation of fenugreek.

Rhizobia-legume symbiosis depends on molecular dialog, which involves the production of specific plant flavonoid compounds as signal molecules. Rhizobium tibeticum was recovered from the root nodule of fenugreek and identified by sequencing the 16S rRNA gene. The effect of salinity stress on nod gene expression was measured in terms of b-galactosidase activity. R. tibeticum containing Escherichia coli lacZ gene fusions to specific nodulation (nod) genes were used to determine b-galactosidase activity. Combination of hesperetin (7.5 mM) and apigenin (7.5 mM) significantly increased b-galactosidase activity more than the single application of hesperetin or apigenin. Preincubation of R. tibeticum with hesperetin and apigenin combination significantly alleviates the adverse effect of salinity on nod gene expression and therefore, enhances nodulation and nitrogen fixation of fenugreek.