Seasonal and annual variation in nitrogen mineralization and nitrification along an elevational gradient in New Mexico

Patterns and amounts of nitrogen loss from disturbed ecosystems vary widely. The mineralization of organic nitrogen to ammonium and then nitrification to nitrate are important processes regulating nitrogen cycling rates and nitrogen losses. Nitrification is a significant process because of the production of the nitrate anion which is easily leached or denitrified. Most studies of these processes do not evaluate their seasonal and yearly variations. This study demonstrates that marked seasonal and yearly variations can occur in these processes in different ecosystems and suggests that nitrogen loss or other system properties correlated with one arbitrarily selected collection can be misleading. Spruce-fir and ponderosa pine ecosystems demonstrated little actual orpotential nitrification. Aspen and mixed conifer ecosystems demonstrated distinct seasonal patterns with increased rates of mineralization and nitrification during spring and summer months and a precipitous decline in both rates coincident with autumn foliage litterfall.The relative availability of soil nitrogen along with the amount of nitrogen circulating annually in litterfall prior to disturbance are useful predictors of the potential for nitrate production and loss following disturbance. However, other controls, including regulation by organic compounds, appear important in determining seasonal and annual variation in actual nitrification rates.     

Blood pressure characteristics of a select group of North American males,followed for 20 years

This report describes the 20-year blood pressure behaviour of 3869 selected young North American males.Initial mean systolic and diastolic pressures were higher than those recorded five years later; after that pressures increased progressively. The effect of initial selection was evident for the first 10 years of exposure.A significant relationship was demonstrated between all initial systolic and diastolic levels and the 20-year blood pressure behaviour. Systolic pressure was not affected by age until age 50 and diastolic until age 45. After that a significant relationship was demonstrated.In 20 years multiple readings ≥ 140 and/or ≥ 90 mm. Hg were recorded in 26% of the population. Increases in pressure usually extended over many years. Commonly they were labile, fluctuating above and below 140/90 mm. Hg. In a small, clearly defined group, accelerated increases reached high levels in three to 10 years.     

The University of Manitoba Follow-up Study: A Prospective Investigation of Cardiovascular Disease: Part I. General Description—Mortality and Incidence of Coronary Heart Disease

A prospective study of cardiovascular disease was initiated in 1946 whereby 3983 healthy North American males, 91% under age 40, were subjected to periodic electrocardiograms and medical examinations between 1948 and 1963. The health of all but five of the 3773 survivors was known in 1963. There were 210 deaths: aircraft accidents accounted for 45%, cardiovascular disease 20%, cancer 11% and other causes 23%. The aggregate mortality closely resembled that of the Canadian Life Table 1955-57 (Male). Extra deaths were observed under age 40 owing to a high frequency of flying accidents. At older ages the mortality was lower than expected because congenital and chronic diseases were excluded at entry. One hundred and forty-three developed coronary heart disease. The case fatality rate was 31%. The incidence rate for coronary heart disease rose progressively from 0.277 per thousand per year for ages 25-34 to 26.5 at ages 60-69.     

Variation in terricolous bryophyte and macrolichen vegetation along primary gradients in Canadian boreal forests

Abstract. Compositional variation among 172 boreal forests stands, based upon the understorey terricolous bryophyte and macrolichen vegetation, is compared with that based upon vascular vegetation. Detrended correspondence analysis (DCA) of the two datasets yielded stand ordinations each indicating a single dominant upland-bottomland gradient. This was most clear among 138 stands in the cryptogam dataset. Canonical correspondence analysis (CCA) of the 138 stand subset yielded a pronounced first axis gradient from dry, nutrient poor pine dominated forest sites to moist, nutrient rich bottomland sites dominated by balsam poplar woodland. Individual species response curves, by the method of log-linear least squares regression, yielded three different respective patterns among the most abundant tree, understorey vascular and cryptogamic plant species. Whereas curves for the tree species were ‘Gaussian’ in shape and displaced at somewhat regular intervals along the gradient, the abundant understorey vascular plant species curves clustered in the mesic, mixed wood region two thirds of the way along. Curves for the abundant cryptogams were mostly linear in shape and absent from the mixed wood zone, showing concentrations at one end of the gradient or the other. Two interpretations of the understorey pattern are considered. One proposes competitive exclusion of cryptogams from the mesic mixed wood region by the vascular understorey plants. Another proposes that the cryptogams are adapted to the sharply contrasting ecosystems encountered at one end of the gradient or another but that none can effectively cope with the intermediate, mixed wood ecosystems. Evidence from the response curves favours this second interpretation.     

Sperm morphology in the Malagasy rodents (Muroidea: Nesomyinae)

The morphology of the spermatozoon of representative species of the subfamily Nesomyinae (Muroidea: Nesomyidae), a monophyletic group of rodents endemic to Madagascar, was examined by light and electron microscopy to determine the sperm head shape and tail length across the species. Marked interspecific differences were found to occur in both the form of the sperm head and length of the tail. The species that possess a sperm head with an apical hook, which largely contains acrosomal material, generally displayed longer sperm tails, and a species with a spatulate sperm head had the shortest tail. The association between sperm head shape and tail length mirrors that previously found in Eurasian and Australasian murine rodents. Thus, the repeated association between sperm head shape and tail length across these groups of muroid rodents clearly indicates a functional relationship between these two features. A comparison of sperm morphology of the nesomyines to that of related muroid rodents on the mainland of Africa suggests that the possession of an apical hook is the ancestral condition. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.     

Discovery of a second generation agonist of the orphan G-protein coupled receptor GPR119 with an improved profile

The design and synthesis of a second generation GPR119-agonist clinical candidate for the treatment of diabetes is described. Compound 16 (APD597, JNJ-38431055) was selected for preclinical development based on a good balance between agonist potency, intrinsic activity and in particular on its good solubility and reduced drug-drug interaction potential. In addition, extensive in vivo studies showed a more favorable metabolic profile that may avoid the generation of long lasting metabolites with the potential to accumulate in clinical studies.     

Inhibition of sickle red cell adhesion and vasoocclusion in the microcirculation by antioxidants

In sickle cell anemia (SCA), inflammatory (i.e., intravascular sickling and transient vasoocclusive) events result in chronic endothelial activation. In addition to sickling behavior, sickle (SS) red blood cells exhibit abnormal interaction with the vascular endothelium, which is considered to have an important role in initiation of vasoocclusion. Upregulation of endothelial adhesion molecules caused by oxidants (and cytokines) may lead to increased SS red cell adhesion. We hypothesize that endothelial activation is indispensable in SS red cell adhesion to the endothelium and that antioxidants will have an inhibitory effect on this interaction. We examined the effect of selected antioxidants in ex vivo mesocecum vasculature, a well-established model that allows measurement of hemodynamic parameters and, by intravital microscopy, can allow quantification of adhesion. We tested antioxidant enzymes (SOD and catalase) and an intravascular SOD mimetic, polynitroxyl albumin (PNA), in the presence of platelet-activating factor (PAF); the latter causes endothelial oxidant generation and endothelial activation, which characterize SCA. In ex vivo preparations, PAF not only induced marked endothelial oxidant generation, it also enhanced SS red cell adhesion, resulting in frequent blockage of small-diameter venules. The adhesion, inversely related to venular diameter, and vasoocclusion were markedly inhibited by antioxidants, resulting in improved hemodynamics. PNA, the most effective antioxidant, also abolished SS red cell adhesion in non-PAF-activated preparations. Thus SS red cell adhesion and related vasoocclusion may be ameliorated by antioxidant therapy with a stable and long-acting molecule (e.g., PNA).     

An EST resource for tilapia based on 17 normalized libraries and assembly of 116,899 sequence tags

Background

Large collections of expressed sequence tags (ESTs) are a fundamental resource for analysis of gene expression and annotation of genome sequences. We generated 116,899 ESTs from 17 normalized and two non-normalized cDNA libraries representing 16 tissues from tilapia, a cichlid fish widely used in aquaculture and biological research.

Results

The ESTs were assembled into 20,190 contigs and 36,028 singletons for a total of 56,218 unique sequences and a total assembled length of 35,168,415 bp. Over the whole project, a unique sequence was discovered for every 2.079 sequence reads. 17,722 (31.5%) of these unique sequences had significant BLAST hits (e-value < 10^-10) to the UniProt database.

Conclusion

Normalization of the cDNA pools with double-stranded nuclease allowed us to efficiently sequence a large collection of ESTs. These sequences are an important resource for studies of gene expression, comparative mapping and annotation of the forthcoming tilapia genome sequence.