Population genetics of Cordia alliodora (Boraginaceae), a neotropical tree. 2. Mating system

A multilocus mixed mating model was used to evaluate the mating system of a natural population of Cordia alliodora (Boraginaceae), a neotropical tree. The population was highly outcrossed (t_m = 0.966 ± 0.027), in agreement with results from controlled crosses. Departures from the mixed mating model were evident, suggesting some nonrandom, correlated mating. Pollen pool heterogeneity and variation in estimates of individual outcrossing rates indicated that the population may be genetically substructured. Individual outcrossing rates obtained for the samples taken from within different parts of the same tree indicated reduced levels of outcrossing due to limited sampling of the pollen pool. The incompatibility mechanism in C. alliodora, combined with variation in flowering and stand density, appears to lead to both temporal and spatial substructuring of the population.     

Foliar treatment of potassium nitrate modulates the fermentative and sucrose metabolizing pathways in contrasting maize genotypes under water logging stress

Physiology and Molecular Biology of Plants - The effect of potassium nitrate on the status of fermentative and sucrose metabolizing pathways was studied in two maize (Zea mays L.) genotypes, viz.,...     

Developmental changes in intestinal brush border enzymes of rats prenatally exposed to ethanol

The activities of lactase, sucrase, alkaline phosphatase (AP) and y-glutamyl transpeptidase (gamma-GTP) were studied in the intestinal brush border membranes of pups born to rat mothers exposed to ethanol (1 ml of 30% ethanol daily during gestation) at different days of postnatal development. The activities of lactase (at day 4-20) and sucrase (at day 20-30) were considerably reduced in response to prenatal exposure to ethanol, while AP (at day 4-30) and gamma-GTP activities were significantly enhanced (p < 0.05) at day 4, 8, 14 and 20, but there was no significant difference by day 30 of postnatal development. The observed changes in enzyme activities were corroborated by Western blot analysis of lactase, sucrase and AP. Kinetic studies revealed a change in Vmax without affecting apparent Km of enzymes under these conditions. The present findings suggest that in utero ethanol exposure to rats is embryotoxic and affects the postnatal development of various brush border enzymes, which persist long after the ethanol was withdrawn prior to birth.     

GFAP-Driven GFP Expression in Activated Mouse Müller Glial Cells Aligning Retinal Blood Vessels Following Intravitreal Injection of AAV2/6 Vectors

Background

Müller cell gliosis occurs in various retinal pathologies regardless of the underlying cellular defect. Because activated Müller glial cells span the entire retina and align areas of injury, they are ideal targets for therapeutic strategies, including gene therapy.

Methodology/Principal Findings

We used adeno-associated viral AAV2/6 vectors to transduce mouse retinas. The transduction pattern of AAV2/6 was investigated by studying expression of the green fluorescent protein (GFP) transgene using scanning-laser ophthalmoscopy and immuno-histochemistry. AAV2/6 vectors transduced mouse Müller glial cells aligning the retinal blood vessels. However, the transduction capacity was hindered by the inner limiting membrane (ILM) and besides Müller glial cells, several other inner retinal cell types were transduced. To obtain Müller glial cell-specific transgene expression, the cytomegalovirus (CMV) promoter was replaced by the glial fibrillary acidic protein (GFAP) promoter. Specificity and activation of the GFAP promoter was tested in a mouse model for retinal gliosis. Mice deficient for Crumbs homologue 1 (CRB1) develop gliosis after light exposure. Light exposure of Crb1^−/− retinas transduced with AAV2/6-GFAP-GFP induced GFP expression restricted to activated Müller glial cells aligning retinal blood vessels.

Conclusions/Significance

Our experiments indicate that AAV2 vectors carrying the GFAP promoter are a promising tool for specific expression of transgenes in activated glial cells.     

Activation of wild type p53 function by its mortalin-binding, cytoplasmically localizing carboxyl terminus peptides

The Hsp70 family member mortalin (mot-2/mthsp70/GRP75) binds to a carboxyl terminus region of the tumor suppressor protein p53. By in vivo co-immunoprecipitation of mot-2 with p53 and its deletion mutants, we earlier mapped the mot-2-binding site of p53 to its carboxyl terminus 312-352 amino acid residues. In the present study we attempted to disrupt mot-2-p53 interactions by overexpression of short p53 carboxyl-terminal peptides. We report that p53 carboxyl-terminal peptides (amino acid residues 312-390, 312-352, 323-390, and 323-352) localize in the cytoplasm, whereas 312-322, 337-390, 337-352, and 352-390 locate mostly in the nucleus. Most interestingly, the cytoplasmically localizing p53 peptides harboring the residues 323-337 activated the endogenous p53 function by displacing it from p53-mortalin complexes and relocating it to the nucleus. Such activation of p53 function was sufficient to cause growth arrest of human osteosarcoma and breast carcinoma cells.     

Influence of ethanol on methanol-induced oxidative stress and neurobehavioral deficits

The present study examines the efficacy of ethanol as an antidote in methanol neurotoxicity in terms of its effect on antioxidant defense system and behavior. It was observed that acute methanol exposure (7.5 g/kg body weight) led to an increase in lipid peroxidation in various regions of brain. Ethanol administration (7.5 g/kg body weight), on the other hand, was found to accentuate methanol-induced lipid peroxidation. Glutathione levels in brain were significantly reduced in methanol-exposed animals. However, in the coexposed animals, the levels of glutathione were comparable to those observed in controls. The activities of superoxide dismutase and catalase were decreased in the brain following methanol exposure, whereas in methanol- and ethanol-coexposed animals there was no significant effect on these enzymes as compared to methanol-exposed animals. The activity of acetylcholinesterase was significantly reduced in the methanol-exposed animals. On the other hand, acetylcholinesterase activity was not affected in the coexposed animals in comparison to methanol-treated group. Neurobehavioral studies revealed impaired motor and cognitive functions following methanol exposure. In contrast, ethanol exposure ameliorated the behavioral deficits induced by methanol. The findings from the present study suggest the beneficial effect of ethanol on neurobehavioral deficits induced by methanol along with intensification of methanol-induced oxidative stress.     

Synthetic peptides derived from the sequence of a lasso peptide microcin J25 show antibacterial activity

Microcin J25 (MccJ25) is a plasmid-encoded, ribosomally synthesized antibacterial peptide with a unique lasso structure. The lasso structure, produced with the aid of two processing enzymes, provides exceptional stability to MccJ25. We report the synthesis of six peptides (1-6), derived from the MccJ25 sequence, that are designed to form folded conformation by disulfide bond formation and electrostatic or hydrophobic interactions. Two peptides (1 and 6) display good activity against Salmonella newport, and are the first synthetic derivatives of MccJ25 that are bactericidal. Peptide 1 displays potent activity against several Salmonella strains including two MccJ25 resistant strains. The solution conformation and the stability studies of the active peptides suggest that they do not fold into a lasso conformation and peptide 1 displays antimicrobial activity by inhibition of target cell respiration. Like MccJ25, the synthetic MccJ25 derivatives display minimal toxicity to mammalian cells suggesting that these peptides act specifically on bacterial cells.