In vitro regeneration and optimization of conditions for Agrobacterium mediated transformation in jute, Corchorus capsularis

Jute is a crop of commercial importance that is widely cultivated for its bast fiber production but susceptible to many diseases that results in major economic loss. New genes can be introduced into this plant through Agrobacterium mediated genetic transformation for its genetic improvement, which is dependent on the availability of suitable in vitro techniques. An efficient regeneration system has been developed for in vitro culture of jute (Corchorus capsularis) from the distal cut ends of cotyledonary petioles. High frequency shoot regeneration was obtained on Murashige and Skoog (MS) nutrient agar medium supplemented with 0.5 mg/l NAA, 0.5 mg/l BAP and 36 g/l sucrose. On transfer to soil, the regenerated plantlets survived and appeared to be morphologically similar to the normal seed-grown plants. They developed pods and set fertile seeds. Histological analysis revealed de novo origin of shoot buds in the in vitro cultured cotyledonary petioles. Parameters affecting transformation were optimized by assaying GUS activity in these regenerable tissues after cocultivation with Agrobacteria. These tissues appear to be susceptible for infection and transformation by Agrobacterium carrying uid (GUS INT) and nptII genes, as well as shoot multiplication. The cells at the cut end of the petioles were found competent to take up the DNA, which was monitored by transient GUS gene expression. EHA105 at 0.3 O.D and LBA4404 at 0.5 O.D were found to be compatible in giving optimal levels of transient GUS expression.     

Simultaneous production of glucose oxidase and catalase by Alternaria alternata

Summary A number of factors affecting simultaneous production of cell-bound glucose oxidase and catalase by the fungus Alternaria alternata have been investigated. Consecutive optimization of the type and concentration of nitrogen and carbon source, the initial pH and growth temperature resulted in a simultaneous increase in glucose oxidase and catalase by 780% and 68% respectively. Two second-order equations, describing the combined effect of pH and temperature on the activity of each enzyme, revealed that glucose oxidase had its optima at pH 7.9 and 32.3°C and catalase at pH 8.5 and 18.1°C. Under certain growth conditions, yields as high as 23.5 and 18,100 units/g carbon source for glucose oxidase and catalase, respectively, were simultaneously obtained.Offprint requests to: B. J. Macris     

Modulation of erythrocyte acetylcholinesterase by cardiolipin: Effect on subunit coupling revealed by irradiation inactivation

The functional molecular weights of two kinetically distinct forms of bovine erythrocyte acetylcholinesterase were determined by irradiation inactivation. Whereas both forms have similar molecular weights by hydrodynamic measurements and contain 33 molecules of cardiolipin, the functional molecular weight of form α (140,000) was found to be twice that of form β (73,000). As form β is derived from form α by treatment with high salt concentration in alkaline Ca²⁺-chelating conditions, a procedure which is considered to disrupt the functional association of a Ca²⁺-cardiolipin complex with the enzyme, it is suggested that cardiolipin mediates the energy transfer between enzyme subunits, thereby modulating the kinetic properties of the lipoprotein.     

The lens epithelium and radiation cataract

The effect of radiation upon the differentiating meridional row cells of the rat lens epithelium was studied by electron microscopy. X-irradiation of rat lenses was shown to disrupt the nuclear and, in some instances, the cytoplasmic organization of these cells. Indications of damage, 4.5 h post-irradiation, are a disruption in the shape of the nucleus and its membranes. This is typified by a bulging or blebbing of the nucleus. At 12 h the affected nuclei deteriorate with obvious membrane breakdown. The nucleoplasm at this time may appear highly condensed and shrunken. Disruption of the plasma membrane is also evident. Based upon previous findings it is likely that the nuclear changes are independent of the processes involved in normal fiber denucleation.     

An Apparatus for Rapid Attachment of Frozen Tissue to Cryostat Tissue Carriers

A brass cylindrical container 11.5 cm high and 7.5 cm in diameter was housed in an insulated wooden box. A 2.2 cm diameter hole was drilled in the centre of the removable brass lid on the underside of which a holder was attached for a cryostat tissue carrier. The container was filled with a mixture of acetone and solid CO₂ to within 1.5 cm of the lid. The frozen tissue was placed in a drop of water on a tissue carrier which was then lowered into the holder through the hole in the lid. The tissue carrier was rapidly cooled by the acetone-solid CO₂ mixture thus freezing the water and attaching the tissue to the carrier.