Model development and behavioral assessment of focal cerebral ischemia in rats

Stroke in humans is usually focal and occurs in the Middle Cerebral Artery (MCA) distribution. There are several rat models that mimic strokes clinically seen in human. Severity of ischemia can be determined by occlusion time, arteries occluded i.e. MCA alone or combined with one or both Common Carotid Arteries (CCA), and/or location of the occlusion. In this study three focal cerebral infarctions (stroke) were induced for 90 and 120 minutes due to the occlusion of: the MCA alone (MCAo); MCA plus unilateral CCA (MCAo+1CCAo); and MCA plus bilateral CCA (MCAo+2CCAo). Histological parameters included infarct lesion size and hemispheric swelling. Since functional recovery of clinical deficits in stroke often correlates with the efficacy of anti-ischemic therapy, we focused on the behavioral recovery. We combined many sources to obtain comprehensive guidelines for clinical behavior evaluation. Tests included limb flexion, torso twisting, circling, lateral push resistance, beam balancing and walking, hindlimb placing, and inverted angle-board gripping. Occlusion lasting 90 minutes was found to have consistent and repeatable deficits. Results from our study demonstrate 120 minutes of occlusion produced a 60% morality rate and was therefore dropped. Body weight changes between groups showed that increased occlusion time produced more weight loss. Behavior changes indicated that MCAo+2CCAo for 90 minutes demonstrated assessable and consistent clinical deficits for the screening of potential therapeutics.     

CHROMOSOME NUMBERS IN UMBELLIFERAE. II

Bell , C. Ritchie (U. of North Carolina, Chapel Hill.), and Lincoln Constance . Chromosome Numbers in Umbelliferae. II. Amer. Jour. Bot. 47(1) : 24-32. Illus. 1960.–Chromosome numbers are reported for plants representing an additional 100 taxa of Umbelliferae. Chromosome numbers for 77 of these taxa are published here for the first time, previously published chromosome numbers of 19 taxa are verified, and numbers differing from those previously published are reported in 4 instances. Ten of the genera included here have been previously unknown cytologically. Polyploidy has been discovered in Bowlesia and confirmed in Pimpinella. Aneuploid series appear to occur in Eremocharis, Eryngium, Oenanthe, Perideridia, and Ptilimnium. Every chromosome count is referable to a cited herbarium specimen.     

Identification of Genetic Factors Contributing to Heterosis in a Hybrid from Two Elite Maize Inbred Lines Using Molecular Markers

The use of molecular markers to identify quantitative trait loci (QTLs) affecting agriculturally important traits has become a key approach in plant genetics-both for understanding the genetic basis of these traits and to help design novel plant improvement programs. In the study reported here, we mapped QTLs (and evaluated their phenotypic effects) associated with seven major traits (including grain yield) in a cross between two widely used elite maize inbred lines, B73 and Mo17, in order to explore two important phenomena in maize genetics-heterosis (hybrid vigor) and genotype-by-environment (G x E) interaction. We also compared two analytical approaches for identifying QTLs, the traditional single-marker method and the more recently described interval-mapping method. Phenotypic evaluations were made on 3168 plots (nearly 100,000 plants) grown in three states. Using 76 markers that represented 90-95% of the maize genome, both analytical methods showed virtually the same results in detecting QTLs affecting grain yield throughout the genome, except on chromosome 6. Fewer QTLs were detected for other quantitative traits measured. Whenever a QTL for grain yield was detected, the heterozygote had a higher phenotype than the respective homozygote (with only one exception) suggesting not only overdominance (or pseudooverdominance) but also that these detected QTLs play a significant role in heterosis. This conclusion was reinforced by a high correlation between grain yield and proportion of heterozygous markers. Although plant materials were grown and measured in six diverse environments (North Carolina, Iowa and Illinois) there was little evidence for G x E interaction for most QTLs.     

Complexation of lithium(I), sodium(I), silver(I) and thallium(I) by 4,7,13,16-tetraoxa-1,10-diazabicyclo[8.5.5]eicosane and 4, 7, 13-trioxa-1,10-diazabicyclo[8.5.5]eicosane in trimethyl phosphate. A potentiometric titration and Li and Na nuclear magnetic resonance study

Complexation of M⁺=Li⁺, Na⁺, Ag⁺ and TI⁺ by the cryptands 4, 7, 13, 18-tetraoxa-l, 10-diazabicyclo[8.5.5]eicosane (C211) and 4,7,13-trioxa-1,10-diazabicyclo[8.5.5]eicosane (C21C₅) to form the cryptates [M.C211]⁺ and [M.C21C₅]⁺ has been studied in trimethyl phosphate by potentiometric titration and ⁷Li and ²³Na NMR spectroscopy. For [M.C211]⁺ the logarithm of the apparent stability constants, log K (dm³ mol^-1)=6.98±0.05, 5.38±0.05, 9.82±0.02 and 3.95±0.02 for M⁺ =Li⁺, Na⁺, Ag⁺ and TI⁺, respectively; and for [M.C21C₅]⁺ log K (dm³ mol^-1)=2.40±0.10, 1.90±0.05, 6.04±0.02 and 2.42±0.10 for M⁺=Li⁺, Na⁺, Ag⁺ and Tl⁺, respectively. The decomplexation kinetic parameters for [Na.C211]⁺ are: k_d (298.2 K)=6.924±0.50 s^-l, ΔH_d≠=62.2±0.9 kJ mol^-1, and ΔS_d≠= -20.3±2.7 J K^-1 mol^-1; and those for [Li.C21C₅]⁺ are: k_d (298.2 K)=23.3±0.4 s^-1, ΔH_d≠ =61.2±1.1 kJ mol^-1, and ΔS_d≠= -13.6±3.6 J K^-1 mol^-1. Metal ion exchange on [Li.C211]⁺ is in the very slow extreme of the NMR timescale up to 390 K and k_d « 4 s^-1 at 298.2 K, while in contrast exchange on [Na.C21C₅]⁺ is in the fast extreme of the NMR timescale at 298.2 K (k_d≈ 10⁴ s^-1). These data are compared with those obtained in other solvents.     

Microwave oven and boiling waterbath extraction of hepatotoxins from cyanobacterial cells

Low-cost, straightforward methods for the extraction of microcystins and nodularins from cyanobacterial cells were developed using a microwave oven and boiling waterbath. The use of organic solvents, such as methanol, which can interfere with sensitive analytical procedures, e.g. immunoassays, can thus be avoided. Analysis by protein phosphatase inhibition assay and high performance liquid chromatography indicated that purified microcystin-LR was unaffected by the microwave oven and boiling waterbath treatments. Four microcystins of differing hydrophobicities were successfully extracted from Microcystis PCC 7813 by both treatments at yields equivalent to those obtained by longer protocols using methanol. Assessment of the microwave oven and boiling waterbath extraction methods with laboratory strains and environmental samples of cyanobacteria showed good correlation with results from lyophilisation and methanol extraction, when extracts were analysed by high performance liquid chromatography with diode array detection (R(2)>/=0.92). The microwave and boiling waterbath extraction methods also sterilised the environmental bloom samples, as evidenced by the abolition of heterotrophic bacterial growth.     

Ecological Relationships of Meso-Scale Distribution in 25 Neotropical Vertebrate Species

Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km² to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species (deviance explained ranging from 21.0 to 54.5%). The group and species GLMs showed some novel ecological information from this relatively pristine area. We found no association between large cats and their potential prey. We also found that rodent and bird species were more often recorded closer to streams. As hunters gain access via rivers this finding suggests that there is currently little anthropogenic impact on the species. Our findings provide a standardized baseline for comparison with other sites and with which planned management and extractive activities can be evaluated.     

Genetic mapping of a gene causing hypertension in the stroke-prone spontaneously hypertensive rat.

The stroke-prone spontaneously hypertensive rat (SHRSP) is a well-characterized model for primary hypertension in humans. High blood pressure in SHRSP shows polygenic inheritance, but none of the loci responsible have previously been identified. To locate genes controlling this quantitative trait, we mapped a large collection of DNA polymorphisms in a cross between SHRSP and the normotensive WKY strain. Here we report strong genetic evidence that a gene, Bp1, having a major effect on blood pressure maps to rat chromosome 10 with a LOD score of 5.10 and is closely linked to the rat gene encoding angiotensin-converting enzyme (ACE), an enzyme that plays a major role in blood pressure homeostasis and is an important target of anti-hypertensive drugs. We also find significant, albeit weaker, linkage to a locus, Bp2, on chromosome 18. We discuss the implications of genetic dissection of quantitative disease-related phenotypes in mammals.     

The SNP Consortium website: past,present and future

The SNP Consortium website (http://snp.cshl.org) has undergone many changes since its initial conception three years ago. The database back end has been changed from the venerable ACeDB to the more scalable MySQL engine. Users can access the data via gene or single nucleotide polymorphism (SNP) keyword searches and browse or dump SNP data to textfiles. A graphical genome browsing interface shows SNPs mapped onto the genome assembly in the context of externally available gene predictions and other features. SNP allele frequency and genotype data are available via FTP-download and on individual SNP report web pages. SNP linkage maps are available for download and for browsing in a comparative map viewer. All software components of the data coordinating center (DCC) website (http://snp.cshl.org) are open source.