UV-B Induced Alterations in Composition of Thylakoid Membrane and Amino Acids in Leaves of Rhizophora Apiculata Blume

Seedlings of Rhizophora apiculata were exposed to UV-B radiation at four doses equivalent to 10, 20, 30, and 40 % ozone depletion. The seedlings irradiated with high doses of UV-B had characteristic decline in contents of specific proteins with molecular masses of 33, 23, and 17 kDa. On the contrary, proteins of 55, 33, 25, 23, and 17 kDa were accumulated in the seedlings exposed to low doses of UV-B. The UV-B, in general, enhanced formation of saturated fatty acids and reduced unsaturated fatty acids, to a maximum extent of 88 and 26 %, respectively. The low dose of UV-B increased content of oleic acid by 9 %, and the high dose reduced it by 34 %. The high dose of UV-B enhanced the lipid peroxidation by 48 %, whereas the low dose of UV-B did not show any significant effect. The contents of amino acids such as aspartate, glutamate, asparagine, serine, glutamine, threonine, and histidine were increased in low UV-B doses by 53, 86, 142, 72, 3, 119, and 32 %, respectively; while in high doses they were reduced significantly.     

How long should angiotensin-converting enzyme inhibitors be given to patients following myocardial infarction: implications of the HOPE trial

Long-term treatment with angiotensin-converting enzyme inhibitors reduces post-infarction morbidity and mortality in patients with left ventricular (LV) systolic dysfunction or symptomatic heart failure. Until recently, the effect of such treatment in patients with preserved LV function has not been known. The results from the Heart Outcome Prevention Evaluation trial have indicated that long-term treatment with ramipril leads to a significant reduction in cardiovascular events in patients with atherosclerotic disease, including those with prior myocardial infarction and preserved LV function. These results suggest that long-term angiotensin-converting enzyme inhibition should also be considered in post-infarction patients with normal cardiac function.     

Physiological responses of mangrove seedling to triacontanol

In viviparous hypocotyls ofRhizophora apiculata Blume the triacontanol treatment enhanced the growth of root and shoot (number of primary and secondary roots, length of roots, shoot height and biomass) protein and energy contents of leaves and roots,in vivo nitrate reductase activity, contents of chlorophylls and carotenoids in leaves as well as the amount of chlorophylls present in photosystems 1 and 2 and in the light harvesting complex of chloroplasts. These promotory effects were recorded at 40 and 80 mg m^-3 triacontanol, but they decreased with increasing growth regulator concentration. Communicated by Z. ŠESTáK     

Use of transferred nuclear overhauser effects to determine the conformation of 1-(3,4-dichlorophenyl)-2-aminopropane when bound to the active site of phenylethanolamine N-methyltransferace (PNMT)

Transferred two dimensional nuclear Overhauser effect spectroscopy (transferred NOESY) was used to show that the side chain of 1-(3,4-dichlorophenyl)-2-aminopropane (1) exists when bound at the active site of PNMT in an extended conformation (τ₂=167 – 180°) with the aromatic ring rotated out of the plane of the ethylamine side chain (τ₁ = 29 – 45°).     

Reversion of anE. coli strain carrying an IS1-activatedbgl operon under nonselective conditions is predominantly due to deletions within the structural genes

Thebgl operon ofEscherichia coli, which encodes the genes necessary for transport and catabolism of β-glucosides, is silent in wild-type cells and is activated by the transposition of IS elements. The silent form of the operon appears to be the stable state. We isolated Bgl^- revertants of an activated strain after growth under nonselective conditions to understand whether activation of the cryptic operon by IS elements is reversible. Genetic and molecular analyses revealed that a majority of revertants carry deletions of thebgl structural genes, indicating that an irreversible alteration has occurred in the operon. Implications of these results for the evolution and maintenance of cryptic genes are discussed. [Yakkundi A., Moorthy S. and Mahadevan S. 1998 Reversion of anE. coli strain carrying an IS1-activatedbgl operon under nonselective conditions is predominantly due to deletions within the structural genes.J. Genet. 77, 21–26]     

Antigenic and catalytic disparity in the distribution of cytochrome P-450-dependent 25-hydroxyvitamin D3-1 alpha- and 24-hydroxylases

Chick 25-hydroxyvitamin D3-1 alpha-hydroxylase, a cytochrome P-450 monooxygenase with a molecular weight of 57 kDa, can be isolated as described by Mandel et al. (1990 b). Under normal physiological circumstances, it occurs exclusively in kidney mitochondria. An isozyme of the 1 alpha-hydroxylase, known as the 24-hydroxylase, which uses the same substrate to yield an isomeric product, is also a cytochrome P-450 monooxygenase, has a molecular weight of 55 kDa, and like-wise occurs in kidney mitochondria. The amino-terminal sequences of the first 10 residues of the two isozymes are 100% homologous. Monoclonal antibodies of the IgM class raised against the 1 alpha-hydroxylase, which quantitatively discriminate against other P-450 cytochromes of mitochondrial or microsomal origin, recognize and interact with the 24-hydroxylase as an antigen. In the present study we show that the intestine, which is the only non-renal tissue with demonstrable 24-hydroxylase activity, gives a positive peroxidase-antiperoxidase immunohistochemical reaction using the monoclonal antibodies against the 1 alpha-hydroxylase. The reactions revealed that the antigen in the kidney is restricted to the cortical proximal tubular cells while in the intestine, the antigen is localized in the enterocytes of the villi. In kidney medullary or intestinal crypt cells, or in liver, heart and lung tissues where 1 alpha-hydroxylase or 24-hydroxylase activity could not be detected using cell or tissue homogenates, the immunohistochemical reactions were also negative.(ABSTRACT TRUNCATED AT 250 WORDS)