Phenotypic Integration and the Plasticity of Integration in an Amphicarpic Annual

In annual plants, including amphicarpic annuals, variation in light availability can evoke phenotypic plasticity in multiple traits. We examined plasticity to light availability of vegetative and reproductive performance traits in Amphicarpaea bracteata (Fabaceae) by developing and evaluating three path-analysis models using data from a greenhouse study. To assess whether light availability altered the phenotypic integration of these performance traits, we examined the models' fit to data collected within a high- or a low-light treatment. We also examined whether a single model or alternate models were required to fit data from the two contrasting light treatments. Using our path-analysis approach, we also made comparisons among three population types: shade- and sun-native populations of the widespread variety A. bracteata var. bracteata and sun-native populations of the variety A. bracteata var. comosa. Although each type of population was somewhat distinctive in patterns of integration and in the plasticity of integration, patterns did not correspond to contrasting ecological affinity, i.e., shade- and sun-native population types or to genetic relatedness of the two varieties. Counter to the prediction that selection regimes involving variation in one or more environmental factor favor intermediate levels of integration, phenotypic integration in A. bracteata was very flexible, with plasticity occurring in a trait-by-trait manner. In particular, there was an inverse relationship between aerial and subterranean reproductive modes in low but not high light. Previous studies of amphicarpic annuals have not observed this type of environment-specific life history trade-off.     

Effects of 2-Deoxy-d-Glucose on Methamphetamine-Induced Dopamine and Serotonin Neurotoxicity

Abstract: The mechanisms underlying the neurotoxic actions of methamphetamine (METH) and related substituted amphetamines are unknown. Previous studies with 2-deoxyglucose (2-DG) have suggested that METH-induced neurotoxicity may involve exhaustion of intracellular energy stores. However, because 2-DG also produces hypothermic effects, and because METH's neurotoxic actions are highly susceptible to thermoregulatory influence, previous findings with 2-DG are difficult to interpret. The present studies were undertaken to further examine the influence of 2-DG's glucoprivic and thermic effects in the context of METH-induced dopamine (DA) and serotonin (5-HT) neurotoxicity. 2-DG protected against METH-induced DA neurotoxicity in both rats and mice. In both species, 2-DG, alone or in combination with METH, produced hypothermic effects. METH's toxic effects on brain 5-HT neurons were either unaffected or exacerbated by 2-DG, depending on species, brain region, and dose of METH tested. These results indicate that different mechanisms may underlie METH-induced DA and 5-HT neurotoxicity, and suggest that, as compared with 5-HT neurons, DA neurons are more susceptible to temperature influence, whereas 5-HT neurons are more vulnerable than DA neurons to metabolic compromise. Additional studies are needed to further assess the role of energy stores in the neurotoxic effects of METH and related drugs.     

Chromosomal localization of the met proto-oncogene in the mouse and cat genome

The met proto-oncogene was mapped in the mouse and cat genomes with the use of mouse X hamster and cat X rodent somatic cell hybrid DNA panels. Based on these analyses we assigned the met gene to mouse chromosome 6 and to cat chromosome A2. We also assigned the cat raf-1 proto-oncogene to the A2 chromosome; met and raf-1 are the first cloned DNAs mapped to this linkage group. Using an interspecies backcross we further localized met on mouse chromosome 6 to a position proximal to the beta chain of the T-cell receptor. This places met near the obese locus in a region of mouse chromosome 6 that appears to be homologous with the long arm of human chromosome 7. The close linkage of met to the gene responsible for cystic fibrosis in humans suggests that further genetic analysis of mouse chromosome 6 may be useful in developing a mouse model for the disease.     

Synthesis of glycerol 1,3-dihexadecyl ether

The synthesis of 1,3-dihexadecyloxy-2-propanol (glycerol 1,3-dihexadecyl ether) is reported. The method is applicable to the preparation of other 1,3-disubstituted glycerols where the substituents are not affected by acid or by catalytic hydrogenolysis conditions.     

Effect of temperature on seed production in the invasive grass Glyceria maxima (Hartm.) Holmb. (Poaceae) in South Africa

Temperature is one of the main factors that determine sexual reproduction in terrestrial and emergent aquatic plant species. The effect of temperature on sexual reproduction and seed production of Glyceria maxima (Hartm.) Holmb. in the southern hemisphere is unknown. Glyceria maxima collections in February 2010 at three isolated infestations in KwaZulu-Natal failed to yield a single seed, only empty panicles. Laboratory experiments showed that vernalisation had no consistent effect on seed production. Field- and laboratory-grown plants produced seeds in the 2010/2011 season, because of having sufficient time at optimum temperatures required for seed production (1 491 and 1 585 hours, respectively), compared to a shorter period (1 352 hours) of suitable temperatures during the 2009/2010 growing season. An inadequate period of optimum temperatures (15–25°C) during seed production resulted in the lack of seeds in the field in the 2009/2010 growing season. This study showed that temperature and duration of exposure thereto during the seed-production period play vital roles in G. maxima sexual reproduction.     

Ground wētā in vines of the Awatere Valley,Marlborough: biology,density and distribution

The endemic New Zealand ground wētā (Hemiandrus sp. ‘promontorius’) has a Naturally Uncommon conservation status. This is because of the paucity of information on its density and distribution. Here, the biology, density and distribution of a population of this wētā found in and around vineyards in the Awatere Valley, Marlborough was studied. Wētā density was assessed in vineyards, paddocks and shrublands in this valley. Soil moisture, penetration resistance, pH and organic matter were recorded at locations with and without wētā. Wētā density in vineyards was significantly higher than in either paddocks or shrub habitats. In vineyards, the density of this insect was significantly higher under-vines than in the inter-rows. Higher numbers of this wētā were found in moist soils that required lower force to burrow. Females laid an average of 55 eggs between March and April, which hatched in September. These findings highlight the intersection between agriculture and conservation.     

Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.      

1-Thio-beta-D-galactofuranosides: synthesis and evaluation as beta-D- galactofuranosidase inhibitors

Beta-D-galactofuranosidase is a good chemotherapeutic target for the design of inhibitors, since beta-D-galactofuranose is a constituent of important parasite glycoconjugates but is not present in the host mammals. With this aim, we have synthesized for the first time alkyl, benzyl and aryl 1-thio-beta-D-galactofuranosides by condensation of penta-O-benzoyl-alpha,beta-D-galactofuranose with the corresponding thiols, in the presence of SnCl4as catalyst. The complete chemical and spectroscopical characterization of these compounds showed that the reaction was stereoselective. Debenzoylation with sodium methoxide afforded the beta-S-galactofuranosides in high yield. The thioglycosides were tested as inhibitors of the beta-D- galactofuranosidase of Penicillium fellutanum, using for the first time 4-nitrophenyl-beta-D-galactofuranoside as chromogenic substrate. The 4- aminophenyl-1-thio-beta-D-galactofuranoside, obtained by catalytic hydrogenation of the nitrophenyl derivative, was the best inhibitor being then an adequate ligand for the preparation of an affinity phase aimed at the isolation of beta-d-galactofuranosidases from different sources. Also the inhibitory activity of d-galactono-1, 4-lactone was shown.