Analysis of betalains from fruits of Opuntia species

Betalains are of great taxonomic significance in higher plants and occur only in 10 families of the order Caryophyllales (Centrospermae). They are water-soluble nitrogenous pigments. They can be divided into two major structural groups, the red to red-violet betacyanins and the yellow betaxanthins. Betalains are widely used as natural red food colorant as well as antioxidant potentials. Several methods have been published for the determination of betalain in fruits of Opuntia species. The purpose of the current review is to provide a systematic survey of the analytical techniques for the determination of betalain from fruits of Opuntia species.     

Processing bodies require RNA for assembly and contain nontranslating mRNAs

Recent experiments have defined cytoplasmic foci, referred to as processing bodies (P-bodies), wherein mRNA decay factors are concentrated and where mRNA decay can occur. However, the physical nature of P-bodies, their relationship to translation, and possible roles of P-bodies in cellular responses remain unclear. We describe four properties of yeast P-bodies that indicate that P-bodies are dynamic structures that contain nontranslating mRNAs and function during cellular responses to stress. First, in vivo and in vitro analysis indicates that P-bodies are dependent on RNA for their formation. Second, the number and size of P-bodies vary in response to glucose deprivation, osmotic stress, exposure to ultraviolet light, and the stage of cell growth. Third, P-bodies vary with the status of the cellular translation machinery. Inhibition of translation initiation by mutations, or cellular stress, results in increased P-bodies. In contrast, inhibition of translation elongation, thereby trapping the mRNA in polysomes, leads to dissociation of P-bodies. Fourth, multiple translation factors and ribosomal proteins are lacking from P-bodies. These results suggest additional biological roles of P-bodies in addition to being sites of mRNA degradation.     

Effect of luteinizing hormone releasing hormone analogues on testosterone metabolismin vitro — A study with mature rat ventral prostates

The effects of two luteinizing hormone releasing hormone analogues (a superagonist and an antagonist) on the conversion of testosterone to dihydrotestosterone in homogenates prepared from adult rat ventral prostates were studied. At higher doses, the superagonist showed a significant dose-dependent inhibition of the conversion of testosterone to dihydrotestosterone. In comparison, the antagonist showed only a marginally inhibitory trend. The implications of these observed effects vis-a-vis the use of the analogues in the endocrine management of prostatic cancer have been discussed.     

Effect of bromocriptine on the hypothalamo-pituitary function in adult male rats.

Daily oral administration of bromocriptine (50 μg/kg) to adult male rats, suppressed serum prolactin levels. The pituitary prolactin levels remained unaltered. Serum FSH levels as well as pituitary FSH levels showed no significant change as compared to the controls. Serum LH levels were significantly decreased in spite of the high pituitary LH levels, in bromocriptine treated rats. In the drug treated rats, $\text{in vitro}$ sensitivity of the pituitary to the exogenous LH-RH was not altered; whereas hypothalamic LH-RH content was considerably lowered. These observations suggest the possible effect of bromocriptine on the synthesis of LH-RH in the hypothalamus which leads to the accumulation of LH in the pituitary and decline of serum LH.