Effect of n-alcohols on the structure and stability of the Drosophila odorant binding protein LUSH

LUSH is an odorant binding protein expressed in the olfactory organs of Drosophila melanogaster that is required for the detection of alcohol in adult flies. Here we demonstrate that, in the absence of ligand, in vitro LUSH exists in a partial molten globule state. The presence of short-chain n-alcohols at pharmacologically relevant concentrations less than 50 mM shifts the conformational equilibrium to a more compact state that exhibits reduced binding of the fluorescent dye 1-anilino-8-naphthalenesulfonic acid. Equilibrium unfolding studies of LUSH-alcohol complexes reveal that, for a series of short-chain n-alcohols, each methylene group can contribute approximately 1 K cal mol(-1) to the overall stability of the protein-alcohol complex. Using NMR spectroscopy, we have identified the regions of LUSH that show increased conformational stability on binding alcohols. These residues primarily line the alcohol-binding pocket. The results presented here provide a direct measure of the degree of stability that alcohol imparts on LUSH. These observations may represent a model for how ethanol can stabilize alternative protein conformations in alcohol-sensitive human proteins and ultimately lead to the observed changes in higher order function throughout the central nervous system.     

Nonlinear stability analyses of vegetative pattern formation in an arid environment

The development of spontaneous stationary vegetative patterns in an arid isotropic homogeneous environment is investigated by means of various weakly nonlinear stability analyses applied to the appropriate governing equation for this phenomenon. In particular, that process can be represented by a fourth-order partial differential time-evolution logistic equation for the total plant biomass per unit area divided by the carrying capacity of its territory and defined on an unbounded flat spatial domain. Those patterns that consist of parallel stripes, labyrinth-like mazes, rhombic arrays of rectangular patches, and hexagonal distributions of spots or gaps are generated by the balance between the effects of short-range facilitation and long-range competition. Then those theoretical predictions are compared with both relevant observational evidence and existing numerical simulations as well as placed in the context of the results from some recent nonlinear pattern formation studies.     

Proteomic analysis of human nail plate

Shotgun proteomic analysis of the human nail plate identified 144 proteins in samples from Causcasian volunteers. The 30 identified proteins solubilized by detergent and reducing agent, 90% of the total nail plate mass, were primarily keratins and keratin associated proteins. Keratins comprised a majority of the detergent-insoluble fraction as well, but numerous cytoplasmic, membrane, and junctional proteins and histones were also identified, indicating broad use by transglutaminases of available proteins as substrates for cross-linking. Two novel membrane proteins were identified, also found in the hair shaft, for which mRNAs were detected only at very low levels by real-time polymerase chain reaction in other tissues. Parallel analyses of nail samples from volunteers from Inner Mongolia, China gave essentially the same protein profiles. Comparison of the profiles of nail plate and hair shaft from the latter volunteers revealed extensive overlap of protein constituents. Analyses of samples from an arsenic-exposed population revealed few proteins whose levels were altered substantially but raised the possibility of detecting sensitive individuals in this way.     

Prevalence of periconceptional folic acid use and perceived barriers to the postgestation continuance of supplemental folic acid: survey results from a Teratogen Information Service

BACKGROUND: Fewer than 40% of U.S. women are taking folic acid supplements periconceptionally at a time when the risk of neural tube defects (NTDs) can be reduced by supplementation. A better understanding of the vitamin-taking habits of childbearing-age women and effective methods for improving periconceptional supplement use are needed. METHODS: A telephone survey conducted through the California Teratogen Information Service (TIS) between August 2003 and January 2004 assessed the prevalence and characteristics of pregnant callers who did not use folic acid supplements in the periconceptional period, and explored attitudes toward advice to continue vitamin use following pregnancy in order to be protected in a future pregnancy. RESULTS: A total of 327 pregnant women who called the TIS for information agreed to participate in the survey. More than half (53.2%) were not taking folic acid-containing supplements in the periconceptional period. Predictors of lack of use included a higher prepregnancy body mass index, younger maternal age, non-white race/ethnicity, lower education level, and unplanned pregnancy. One-quarter of the women said they would be willing to continue taking vitamins after the pregnancy if advised to do so by a physician. The remainder identified obstacles to following that advice--notably, not planning to become pregnant again and the belief that enough folate is derived from diet alone. CONCLUSIONS: More than half of the callers to the TIS were not compliant with recommendations regarding periconceptional folic acid supplementation. This represents an opportunity for TIS specialists and physicians to intervene in a current pregnancy to encourage maintenance of supplement use in the subsequent interpregnancy interval.     

Identification of immunological reagents for use in the study of freshwater planarians by means of whole-mount immunofluorescence and confocal microscopy

In recent years, interest in planarians as a model system for the study of metazoan regeneration, adult stem cell biology, and the evolution of metazoan body plans has been growing steadily. The availability of RNA interference (RNAi), BrdU-labeling of planarian stem cells, and thousands of planarian cDNA sequences soon to be released into public databases has opened planarians to molecular dissection. However, the successful application of large-scale RNAi-based screens, for example, will depend in part on the availability of markers to characterize the resulting phenotypes. Given the paucity of antibodies available for the study of planarian biology, we have screened various public and commercial antibody resources to identify immunoreagents capable of cross-reacting with planarian tissues. Here we report the identification and characterization of 33 such antibodies recognizing a wide variety of tissues in freshwater planarians.     

Edible wild mushrooms of the Cofre de Perote region,Veracruz, Mexico: An ethnomycological study of common names and uses

A field study in the Cofre de Perote region found that edible mushrooms play an important role in the socio-economics activities of the local population. Several very old common names indicate a long-standing traditional knowledge about this regional resource. Recent changes in marketing mushrooms are evident.     

A four-proton-families model for pH-dependent enzyme activation: application to intestinal brush border sucrase.

Current concepts of pH-dependent enzyme function are expanded to consider enzymes with up to four key proton families. In an earlier paper the authors extended classical theory to explain the existence, in the acid ionization reaction, of two functionally distinct, V and K, proton families, exemplified by the 1988 sucrase three-proton-families model of Vasseur et al. They now propose that enzymes having two distinguishable proton families at each side of the pH-activity curves exist in nature although there is no previously published evidence of their existence. The resulting, more general, four-proton-families model is treated as a useful framework from which submodels can be derived by simplification, the simplest being the 1911 linear model of Michaelis and Davidsohn, which took into account two proton families out of the theoretical maximum of four proposed here. It is shown that whether a three-proton-families or a four-proton-families model can explain sucrase better is not merely a question of theory but also involves the practical question of having enough data, at each side of the pH spectrum, to permit making an unequivocal choice between the two alternatives. The paper concludes with a discussion of substrate-induced pK shifts according to both models.