Zea mays ZmMybst1 cDNA,encodes a single Myb-repeat protein with the VASHAQKYF motif

A cDNA clone from a 4 DAP dissected maize embryo sac encoding a novel Zea mays single-repeat Myb protein is reported here. This full-length cDNA contains an ORF of 948 bp. The gene ZmMybst1 contains two introns (1166 and 706 bp) and is a single copy gene. The ZmMybst1 protein shares high sequence identity with the potato Mybst1 protein (58%). Northern blot, RT-PCR and electronic northern analysis shows that ZmMybst1 is expressed in endosperm between 4 and 30 DAP, coinciding with the period of aleurone cell differentiation and development.     

Algal allelopathy

The comprehensive review on allelopathy (Rice, 1979, 1984) has been largely responsible for the evolution of allelopathy as an independent branch of chemical/ physiological ecology. The allelopathic research during the last four decades drew attention to different facets of the interactions among the constituents of habitat, calling for an understanding of the role of allelopathy under different habitat conditions. In view of this, we have reviewed the existing information on allelopathic interactions in aquatic habitats with special reference to algal allelopathy. This review has been mainly confined, therefore, to different aspects of algal allelopathy such as allelopathic interactions in algae, algal toxins, bioassays, and implications of algal allelopathy. In spite of the large number of reviews on allelopathy (see section III), no independent review appears on algal allelopathy. Although there were reports of toxins from cyanobacteria and other algae, no appreciable attempt was made to implicate algal toxins in allelopathy under field conditions. Knowledge of chemistry and biology of allelochemical can help in their potential use in controlling plant diseases and weeds. Therefore, it is urgent to study algal toxins for their involvement in ecological phenomena such as succession, for their uses as herbicides, weedicides, and pesticides, for their uses in solving some of the problems of algal ecology, and for their involvement in applied aspects.     

Peroxisomal participation in the cellular response to the oxidative stress of endotoxin

Exposure to a sublethal dose of endotoxin offers protection against subsequent oxidative stresses. The cellular mechanisms involved in generating this effect are not well understood. We evaluated the effect of endotoxin on antioxidant enzymes in liver peroxisomes. Peroxisomes have recently been shown to contain superoxide dismutase (SOD) and glutathione peroxidase (GPX) in addition to catalase. Peroxisomes were isolated from liver homogenates by differential and density gradient centrifugations. Endotoxin treatment increased the specific activity of SOD and GPX in peroxisomes to 208% and 175% of control activity, respectively. These findings correlated with increases in peroxisomal SOD and GPX proteins observed by immunoblot. Although the quantity of catalase protein was increased when assessed by immunoblot analysis, the specific activity of catalase was decreased to 68% of control activity. Activation of catalase with ethanol only restored catalase activity to control levels suggesting that catalase had undergone irreversible inactivation. The observed increase in GPX activity may represent a compensatory mechanism triggered by accumulating H₂O₂. The data presented here suggest for the first time that mammalian peroxisomal antioxidant enzymes are altered during the oxidative injury of endotoxin treatment.     

Levels and syntheses of cerebrosides and sulfatides in subcellular fractions of jimpy mutants

During the period of brain development, the levels of nonhydroxy- and hydroxy-cerebrosides in the cytosol from brains of jimpy mutants were determined by high-performance liquid chromatography and compared to those in the rest of the particulates from the same brains as well as those in the littermate controls. The concentrations of cerebrosides in jimpy brain preparations were much lower than in controls at all ages. In another experiment, [U-¹⁴C]glucose was injected intraperitoneally into jimpy mutants and their littermate controls. The amounts of radioactivity incorporated into cerebrosides and sulfatides in brain cytosol, the microsome-rich fraction, and the rest of the heavier particles were determined. Although the total radioactivity incorporated into these lipids was much lower in jimpy, the specific activities were 2–3 times the control value in all subcellular fractions.     

Invasive marine algae: An ecological perspective

The significance of marine algal invasion is undisputed in the global context; however, this topic has not received as much attention as it deserves. Although substantial evidence supports the fact of marine algal introduction and invasion, the underlying ecological principles need more attention to better explain such invasions. Marine algal invasions transcend national boundaries, so the problem must be considered an international problem. Commercial exploitation of invasive marine algae (and under this category we include deliberate introductions) should be undertaken, if at all, with great care and with a full understanding of all aspects of the biology and ecological consequences of the new exotic species. The aim of this article is to define algal invaders from a marine ecosystem standpoint and to discuss the different vectors, their dispersal patterns, and mechanisms of their dominance in their naturalized or introduced range     

Effect of Rhinovirus Challenge on Antioxidant Enzymes in Respiratory Epithelial Cells

The host inflammatory response appears to be an important contributor to the pathogenesis of human viral respiratory illness. Virus-induced oxidative stress appears to mediate an early phase of elaboration of the proinflammatory cytokine interleukin-8 by respiratory epithelial cells. The purpose of these studies was to determine if virus-induced alterations in either the expression or function of antioxidant enzymes contributes to the cellular oxidative stress following rhinovirus challenge. The activities of Mn superoxide dismutase (MnSOD), catalase and glutathione peroxidase (GPX) were not significantly changed by rhinovirus challenge. CuZn superoxide dismutase (CuZnSOD) activity six hours after challenge was 2.55 &#45 0.56 U/mg protein in rhinovirus-challenged cells compared to 1.16 &#45 0.54 U/mg protein in control cells ( p =0.029). This increased activity was associated with a concomitant increase in CuZnSOD mRNA and protein concentration. These data suggest that rhinovirus-induced changes in the host cell redox state that result in the early elaboration of interleukin-8 are not mediated by inhibition of either the expression or function of these antioxidant enzymes.