Trees on networks: resolving statistical patterns of phylogenetic similarities among interacting proteins

Background  

Phylogenies capture the evolutionary ancestry linking extant species. Correlations and similarities among a set of species are mediated by and need to be understood in terms of the phylogenic tree. In a similar way it has been argued that biological networks also induce correlations among sets of interacting genes or their protein products.     

Cellular and molecular biology of Alzheimer's disease

Alzheimer's disease results from the degeneration of neurons. Degenerating nerve cells express atypical proteins, and amyloid is deposited. We suggest that some of these events are strongly influenced by genetic factors and age. Animal models should be useful in investigating the pathogenic mechanisms that lead to the brain abnormalities seen in this disease.     

Ionic fluxes induced by topical misoprostol in canine gastric mucosa

We studied the dose response of ionic fluxes in canine chambered gastric segment mucosa to increasing doses of topical misoprostol (0.1, 1, 10, 100, and 1000 micrograms). The fluxes were also correlated with the simultaneous changes in focal gastric mucosal blood flow measured by laser-Doppler flowmetry. After misoprostol administration, there was a dose-dependent increase in focal gastric mucosal blood flow (Emax = 8.23 +/- 3.25 V at 10 micrograms; ED50 = 1.05 micrograms), pH, and the outputs of ions (Na+, K+, Cl-, and HCO3-) and fluid (Emax for pH and fluxes greater than or equal to 1000 micrograms). ED50 values for these outputs ranged from 215.40 to 340 micrograms (mean +/- SE = 279.08 +/- 24.27 micrograms). H+ output showed a dose-dependent decrease to zero at the 10-micrograms dose, the dose at and after which net HCO3- secretion became obvious. The slopes of the dose-response curves for the fluxes of fluid, Na+, K+, Cl-, and HCO3- were significantly different (p less than 0.01) from the slope of the curve for mucosal blood flow changes. There were no correlations between the changes in these fluxes and blood flow changes. Na+ and Cl- were the predominant cation (98.84%) and anion (98.19%), respectively, in the misoprostol-induced secretion. Misoprostol stimulates a composite alkaline gastric nonparietal secretion, predominantly Na+ and Cl-, but also containing K+ and HCO3-. Our results suggest different mechanisms for the effects on nonparietal secretion and focal gastric mucosal blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)     

南瓜雌蕊与自花及远缘花粉的相互作用

南瓜柱头表面经去垢剂、蛋白酶及Con A处理后花粉不能萌发或花粉管生长受阻,Con A能专一地与柱头表面结合。柱头块加入培养液可促进花粉萌发。不同的远缘花粉授粉后在雌蕊不同部位受阻。在成熟南瓜雌蕊提取液中检测到血凝活性,凝集素可能参与雌蕊对远缘花粉的抑制。     

Effector cell expression of NK1.1, a murine natural killer cell-specific molecule, and ability of mice to reject bone marrow allografts

The rejection of Hh-1 incompatible bone marrow cells in irradiated mice is mediated by NK cells and is genetically regulated. We tested the role of the NK-specific gene, NK1.1, in regulating the rejection of allogeneic bone marrow cell grafts. NK1.1+ mice, that are known to display strong resistance against Hh-1 incompatible grafts, were crossed to H-2/Hh-1 identical NK1.1-, poor responder mice, and the progeny were backcrossed to the poor responder parent. The segregating mice were individually typed for their expression of NK1.1 and the ability to resist Hh-1 incompatible bone marrow cells (BMC). A strong correlation was noted between expression of NK1.1 and rejection of H-2d/Hh-1d BMC. Our results support the idea that NK1.1 is one of the genes responsible for strong resistance to Hh-1d (determinant 2) but not for Hh-1j (determinant 3) BMC grafts. We suggest that the NK1.1 molecule functions as an accessory molecule in the cellular interactions involving the recognition of Hh-1 determinants.     

Oral inoculation with herpes simplex virus type 1 infects enteric neuron and mucosal nerve fibers within the gastrointestinal tract in mice.

Herpes simplex virus type 1 (HSV-1) is commonly encountered first during childhood as an oral infection. After this initial infection resolves, the virus remains in a latent form within innervating sensory ganglia for the life of the host. We have previously shown, using a murine model, that HSV-1 placed within the lumen of the esophagus gains access to nerves within the gut wall and establishes a latent infection in sensory ganglia (nodose ganglia) of the tenth cranial nerve (R. M. Gesser, T. Valyi-Nagy, S. M. Altschuler, and N. W. Fraser, J. Gen. Virol. 75:2379-2386, 1994). Peripheral processes of neurons in these ganglia travel through the vagus nerve and function as primary sensory receptors in most of the gastrointestinal tract, relaying information from the gut wall and mucosal surface to secondary neurons within the brain stem. In the work described here, we further examined the spread of HSV-1 through the enteric nervous system after oral inoculation. By immunohistochemistry, HSV-1 was found to infect myenteric ganglia in Auerbach's plexus between the inner and outer muscle layers of the gut wall, submucosal ganglia (Meisner's plexus), and periglandular ganglion plexuses surrounding submucosal glands. Virus-infected nerve fibers were also seen projecting through the mucosal layer to interact directly with surface epithelial cells. These intramucosal nerve fibers may be a conduit by which intraluminal virus is able to gain access to the enteric nervous system from the gastrointestinal lumen.     

Production of panose from maltose by intact cells of Aureobasidium pullulans

Panose, a major component of isomalto-oligosaccharides, was selectively produced from maltose using transglucosylation reaction catalyzed by intact cells of Aureobasidium pullulans. When 50 %(w/v) maltose was used as a substrate, the maximum concentration of panose accumulated in the final reaction mixture was about 50 %(w/w) after 120 hr reaction at 55 °C.