Propagation, taxonomy and ecophysiological characteristics of the Azolla-Anabaena symbiosis in freshwater habitats of Beni-Suef Governorate (Egypt).

A new ecotype of Azolla fern has established in freshwater habitats at Beni-Suef Governorate. The fern propagates in shallow irrigation canals and drains with low-velocity water. Azolla fern is circular (fan-like) in shape with a diameter of 2-3 cm; the surface of the fronds is covered with trichomes and contains stomata with annular guard cells and central pores. Azolla is a sterile hybrid, only forming microsporocarps, never megasporocarps: the microsporocarp contains about 64 microsporangia. Each microsporangium consists of 4 massula, each characterized by the presence of anchor-like multiseptate glochidia covering the whole surface of the massula. This ecotype probably belongs to Azolla caroliniana on the basis of vegetative and reproductive characteristics. Growth (biomass yield) is seasonal, with higher biomass (3.0-4.5 kg m-2) and shorter doubling time in summer, reducing to about 1.0-1.5 kg m-2 in winter. Azolla plants accumulated the minerals Fe, Zn, Cu, Ni and Pb when growing in freshwater canals, drains and waste water. Salt stress treatment inhibited growth, nitrogen fixation and protein content. Iinhibitory levels of salinity were about 0.6-0.8 % NaCl. Growth and nitrogen fixation were inhibited at higher levels (2.4 mol m-3 and 5.1 mol m-3) of combined nitrogen (ammonium sulphate and urea). The ecophysiological significance of Azolla in the freshwater habitats of Beni-Suef Governorate is discussed

Selection of an efficient in vitro micropropagation and regeneration system for potato (Solanum tuberosum L.) cultivar Desirée

Sprouts of about 40 to 80 mm length were excised, surface sterilized with 70% CloroxR and cultured on solid full-strength Murashige and Skoog (MS) medium. Shoot nodal segments (1.0 cm) from in vitro plantlets (2 to 4 weeks old) were multiplied through periodic subculturing on full-strength MS medium with 30 g/L sucrose, 100 ml/L myo-inositol and 0.5 ml/L silver thiosulfate. The shoots were rooted on the same medium. Microtubers were stimulated on MS medium supplemented with 80 g/L sucrose, 100 ml/L myo-inositol and 5 ml/L benzyl adenine. They generally originate on aerial etiolated shoots producing . 1.0 } 0.5 microtuber/explant with diameter approx. 3 to 10 mm. Shoot regeneration was performed from  tuber discs, internodes and leaf explants using 6 different media. Different regeneration capacities were  observed by the explants along 60 days. The average number of shoots was highest from tuber discs (6.2)  than from leaf explants (2.6) which exceeds about three times; no shoot from internode explants cultured on the various media. Regenerated plantlets produced from both tuber discs and leaf explants exhibited random amplification of polymorphic DNA (RAPD) analysis using five selected primers to detect  somaclonal variation. All the morphological variants were excluded. One of the regenerated plantlet  derived from leaf-explants was true-to-type to the main in vitro plantlet, so it will be used as a source of explants for transformation experiments. The other regenerated plantlets derived from leaf explants and tuber discs show the presence and/or absence of polymorphic bands. Results also showed that  microtubers were initiated on the etiolated shoots of the regenerants at the first 10 days. The etiolated shoots induced about 2.6 } 0.6 and 2.2 } 0.5 microtuber/explants.Key words: Solanum tuberosum L., seed tuber, sprouting, micropropagation, microtubers, explants, regeneration, random amplification of polymorphic DNA (RAPD)

Biogas Producing Bacteria from Termites

          The human demands for energy and conservation of healthy environment have driven the development of cellulosic wastes into new generation of bioenergy.  Ethanol was the first generation of biofuel developed to lessen dependence on fossil fuels. Efficiency of conversion of cellulosic material into simple sugars was the driving force behind search for strong cellulose-degrading microbes; Termites was chosen to be an excellent candidate to find such microbes. Six bacteria were isolated from the Termite's guts where their cellulose degrading activities were screened using carboxymethyl cellulose as a substrate and Congo red as an indicator. Only one isolate showed a relatively higher cellulolytic activity and biogas production. This isolate was identified by a variety of methods including the MALDI-TOF MS and turned out to be Enterobacter cloacae. The ability of this bacterium to degrade cellulose and produce biogas qualifies it for further development at genetic levels and biotechnological levels to produce biogas from cellulosic wastes