Retransformation of a male sterile barnase line with the barstar gene as an efficient alternative method to identify male sterile–restorer combinations for heterosis breeding

We report in this study, an improved method for identifying male sterile–restorer combinations using the barnase–barstar system of pollination control for heterosis breeding in crop plants, as an alternative to the conventional line × tester cross method. In this strategy, a transgenic male sterile barnase line was retransformed with appropriate barstar constructs. Double transformants carrying both the barnase and barstar genes were identified and screened for their male fertility status. Using this strategy, 66–90% of fertile retransformants (restored events) were obtained in Brassica juncea using two different barstar constructs. Restored events were analysed for their pollen viability and copy number of the barstar gene. Around 90% of the restored events showed high pollen viability and ∼30% contained single copy integrations of the barstar gene. These observations were significantly different from those made in our earlier studies using line (barnase) × tester (barstar) crosses, wherein only two viable male sterile–restorer combinations were identified by screening 88 different cross-combinations. The retransformation strategy not only generated several independent restorers for a given male sterile line from a single transformation experiment but also identified potential restorers in the T₀ generation itself leading to significant savings in time, cost and labour. Single copy restored plants with high pollen viability were selfed to segregate male sterile (barnase) and restorer (barstar) lines in the T₁ progeny which could subsequently be diversified into appropriate combiners for heterosis breeding. This strategy will be particularly useful for crop plants where poor transformation frequencies and/or lengthy transformation protocols are a major limitation.     

Doppler ultrasound scoring to predict chemotherapeutic response in advanced breast cancer

Background

Von Hippel-Lindau (VHL) disease is an autosomal dominant inherited disease. It is relatively recent that type 2C was identified as a separate group solely presenting with pheochromocytomas. As an illustration, an interesting case is presented of a pregnant woman with refractory hypertension. It proved to be the first manifestation of bilateral pheochromocytomas. The family history may indicate the diagnosis, but only identification of a germ line mutation in the DNA of a patient will confirm carriership.

Case presentation

A 27 year pregnant patient with intra uterine growth retardation presented with hypertension and pre-eclampsia. Magnetic resonance imaging revealed bilateral adrenal pheochromocytoma. She underwent laparoscopic adrenelectomy and a missense mutation (Gly93Ser) in exon 1 of the VHL gene on chromosome 3 (p25 - p26) was shown in the patient, her father and her daughter confirming the diagnosis of VHL.

Conclusion

In almost all VHL families molecular genetic analysis of DNA will demonstrate an inherited mutation. Because of the involvement in several organs, periodic clinical evaluation should take place in a well coordinated, multidisciplinary setting. VHL disease can be classified into several subtypes. VHL type 2C patients present with pheochromocytomas without evidence of haemangioblastomas in the central nervous system and/or retina and a low risk of renal cell carcinoma. Therefore, in such families, periodic clinical screening can be focussed on pheochromocytomas.     

A family of amphiphilic dioxidovanadium(V) hydrazone complexes as potent carbonic anhydrase inhibitors along with anti-diabetic and cytotoxic activities

BioMetals - A family of dioxidovanadium(V) complexes (1–4) of the type [Na(H2O)x]+[VVO2(HL1?4)]? (x?=?4, 4.5 and 7) where HL2? represents the dianionic form of...