Direct visualization of IMP--GMP:pyrophosphate phosphoribosyltransferase in polyacrylamide gels

Direct visual detection of IMP-GMP: pyrophosphate phosphoribosyl-transferase (HGPRT) activity after separation by polyacrylamide gel electrophoresis has not been easy to achieve. Radiochemical assays have been used but they have the disadvantage of requiring considerable amounts of time before the results are available (1.2). A fluorescence assay that couples inosine 5′-monophosphate (IMP) to IMP dehydrogenase with concomitant formation of NADH has been described (3) but is inconvenient because the coupling enzyme is not commercially available. Bieber (4) has developed a fluorescence assay that can be used for HGPRT detection but it requires that the gels be sliced before they are incubated with the substrate mixture. A rapid, convenient method for visual observation of HGPRT activity would facilitate the study of this enzyme and its variants. In this paper we report the development of such a method based on precipitation of inorganic pyrophosphate, one of the reaction products, with Mn²⁺.     

Regional analysis of brain opiate receptors in rats with hereditary hypothalamic diabetes insipidus.

The regional distribution of stereospecific ³H-dihydromorphine binding sites in Brattleboro rats with hereditary hypothalamic diabetes insipidus was studied. Control animals were homozygous normal Brattleboro rats and rats heterozygous for the vasopressin deficiency. Scatchard plots of ³H-dihydromorphine binding in a washed membrane preparation showed that rats with diabetes insipidus exhibited higher receptor concentrations in all assayed areas of the cerebral hemispheres. In the diencephalon, receptor concentrations were lower in diabetes insipidus rats. The results point to the existence of interactions between brain opioid systems and neurohypophyseal peptides.     

Effect of urokinase on disseminated intravascular coagulation

Our studyevaluated the possible therapeutic effect of urokinase in treating themicrothrombiotic effects of disseminated intravascular coagulation byassisting the activation of endogenous plasminogen. Twenty-six pigswere anesthetized, intubated, mechanically ventilated, and surgicallycatheterized. Septic shock was induced in all 26 pigs by an intravenousinfusion of heat-killed Escherichia coli. The pigs were divided into two sets ofexperiments: in experiment 2 (n = 14), one-half received anintravenous dose of urokinase 1 h after heat-killed E. coli infusion and in experiment3 (n = 12) one-halfreceived an intravenous bolus dose and a continuous drip of urokinase 2 h after heat-killed E. coli infusion.The untreated pigs served as controls. Hemodynamic parameters, blood chemistries, and blood gases were analyzed. Urokinase given 1 h afterbacterial toxin infusion significantly restored blood flow, resultingin an increase in cardiovascular and pulmonary function and improvedsurvival rate (43% control vs. 100% treated, 24-h experimentalperiod). Treatment given after 2 h showed some significant effect onpulmonary function; however, within 10 h of E. coli infusion, mortality rates in control and treatedgroups were 100 and 83%, respectively. Early administration ofurokinase after onset of disseminated intravascular coagulationrestored blood flow and helped resolve organ damage.

     

Relative genetic diversity of the rare and endangered Agave shawii ssp. shawii and associated soil microbes within a southern California ecological preserve

Shaw''s Agave (Agave shawii ssp. shawii) is an endangered maritime succulent growing along the coast of California and northern Baja California. The population inhabiting Point Loma Peninsula has a complicated history of transplantation without documentation. The low effective population size in California prompted agave transplanting from the U.S. Naval Base site (NB) to Cabrillo National Monument (CNM). Since 2008, there are no agave sprouts identified on the CNM site, and concerns have been raised about the genetic diversity of this population. We sequenced two barcoding loci, rbcL and matK, of 27 individual plants from 5 geographically distinct populations, including 12 individuals from California (NB and CNM). Phylogenetic analysis revealed the three US and two Mexican agave populations are closely related and have similar genetic variation at the two barcoding regions, suggesting the Point Loma agave population is not clonal. Agave‐associated soil microbes used significantly more carbon sources in CNM soil samples than in NB soil likely due to higher pH and moisture content; meanwhile, soil type and soil chemistry analysis including phosphorus, nitrate nitrogen, organic matter, and metals revealed significant correlations between microbial diversity and base saturation (p < 0.05, r ² = 0.3676), lime buffer capacity (p < 0.01, r ² = 0.7055), equilibrium lime buffer capacity (p < 0.01, r ² = 0.7142), and zinc (p < 0.01, r ² = 0.7136). Soil microbiome analysis within the CNM population revealed overall expected richness (H′ = 5.647–6.982) for Agave species, while the diversity range (1 − D = 0.003392–0.014108) suggests relatively low diversity marked by high individual variation. The most prominent remaining US population of this rare species is not clonal and does not seem to be threatened by a lack of genetic and microbial diversity. These results prompt further efforts to investigate factors affecting Agave''s reproduction and fitness.     

America's Most Famous Human Footprints: History,Context and First Description of Mid-Holocene Tracks from the Shores of Lake Managua,Nicaragua

Human tracks discovered in 1874 at a site named El Cauce or Acahualinca near the shores of Lake Managua, Nicaragua, are the most famous and abundant human tracks in the Americas. They represent a landmark ichnological discovery during the late 19th century that generated much debate regarding their age and origins. Reported dates for the tracks range from 2,120 to 6,500 B.P. The site, which is now situated within the limits of Nicaragua's capital city of Managua, forms the basis of the Acahualinca Tracks Museum (Huellas de Acahualinca) and has been in place since 1953. However, it is still little known and has not been systematically studied, despite being an important window into Meso-American prehistory. Two exposures of a surface of volcanic ash reveal hundreds of human tracks comprising a minimum of 12 clearly defined trackways, and a trampled zone or path representing at least three more individuals, all heading in the same northwesterly direction. Tracks of deer, opossum and at least one bird are also present. Bison tracks collected from another nearby site (El Recreo) that is no longer accessible are on display at the museum. The Acahualinca tracks are noteworthy for the exceptional quality of preservation. We herein present the first maps of the two exposures, which combine to tell a story of human and animal activity along the shores of ancient Lake Managua several thousand years ago.