Different relative abundance of neurotensin and neuromedin N in bovine ocular tissues.

Neurotensin (NT) and neuromedin N (NN) are regulatory peptides encoded by the same gene and located in tandem within a common precursor. Using specific radioimmunoassays for both peptides, their relative abundance in extracts of bovine ocular tissues has been examined. Within the retina, the molar concentration of NN was significantly higher (P less than 0.001) than that of NT. In contrast, within both choroid/sclera and iris/ciliary bodies, the molar concentration of NT was significantly higher (P less than 0.001) than that of NN. These data demonstrate that the theoretical molar ratio of 1:1, which would result from complete processing of both peptides from the common precursor, does not occur in any of the ocular tissues examined. Reverse phase HPLC of extracts of each ocular tissue confirmed the differential abundance of NT and NN. These data would suggest that the common NT/NN precursor is differentially-processed within bovine ocular tissues, a finding which may be of physiological significance.     

The population ecology of a natural population of the pierid butterfly Colias alexandra

Summary Key factor analysis techniques were used to examine factors determining the abundance of a population of non-pest Colias. The number of individuals entering each successive life stage in the sample population are summarized in life tables for 1975 to 1979. Survivorship to the adult is a relatively consistent proportionality (-x=1.2%, S.D.=1.14; 1975–1979). Factors resulting in reduced natality and, less importantly, mortality during larval diapause determine the population trends for C. alexandra. Egg mortality, pre-diapause larval mortality and postdiapause mortality contribute little to these trends. Possible key sources contributing to reduced natality are examined. Mortality of adults (including removal by collectors), poor weather conditions during the oviposition period, unseasonal snow or drought which affect nectar sources or oviposition sites are among the factors which cause reduced natality and result in population depression.     

Characterization of preribosomal ribonucleoprotein particles from Tetrahymena pyriformis.

Ribonucleoprotein particles present in extracts of nuclei prepared from Tetrahymena pyriformis labelled for 1, 2.5, 5 and 10 min with [3H]uridine during exponential growth were analysed by sedimentation through linear 10--30% sucrose gradients. After 1 min of labelling, the early ribosomal RNA precursor (36-S) is found to be associated with slowly sedimenting particles which form a broad peak centred at approximately 50 S. Other kinds of particles sedimenting at 80 S, 66 S, 60 S and 44 S are observed when labelling is carried out for longer periods (2.5, 5 and 10 min). The 80-S particle contains 29-S and 18-S RNA species together with traces of 36-S RNA; the 60-S and 44-S particles contain 26-S and 17-S RNAs respectively. Similar results were obtained when [Me-3H]methionine was used for labelling in place of [3H]uridine. Methylation of the RNA present in slowly sedimenting nuclear components (30-70-S) is rapid, reaching a plateau at 5 min while that of the faster sedimenting (70--90-S) components is still increasing after 10 min. Only three types of ribonucleoprotein particles (80-S, 66-S, and 44-S) were observed when the cells were labelled after prolonged starvation. A scheme of ribosome biogenesis based on these results is presented.     

Evaluation of the Epidemic Potential of Western Equine Encephalitis Virus in the Northeastern United States

The problem of evaluating the epidemic potential of western equine encephalitis in the northeastern United States is presented and possible reasons are discussed for the present lack of human and horse cases of this disease even though increased numbers of isolations of the virus have been obtained in the East during recent years. Epidemiologic factors of vector bionomics and virus strain variations are considered. It is concluded that while this virus strain can no longer be regarded as uncommon in the Northeast, the evidence indicates there is little potential for epidemic expression of this agent in the human and horse population. This appears to be due to differences in the bionomics of the mosquito Culiseta melanura, which serves as the primary enzootic vector in the northeastern United States and in the bionomics of Culex tarsalis that is the vector in the western region of the United States. Other limiting factors in the epidemic potential may be variations between virus strains located in the East and West.     

Fast classification and compositional analysis of cornstover fractions using Fourier transform near-infrared techniques

The objectives of this research were to determine the variation of chemical composition across botanical fractions of cornstover, and to probe the potential of Fourier transform near-infrared (FT-NIR) techniques in qualitatively classifying separated cornstover fractions and in quantitatively analyzing chemical compositions of cornstover by developing calibration models to predict chemical compositions of cornstover based on FT-NIR spectra. Large variations of cornstover chemical composition for wide calibration ranges, which is required by a reliable calibration model, were achieved by manually separating the cornstover samples into six botanical fractions, and their chemical compositions were determined by conventional wet chemical analyses, which proved that chemical composition varies significantly among different botanical fractions of cornstover. Different botanic fractions, having total saccharide content in descending order, are husk, sheath, pith, rind, leaf, and node. Based on FT-NIR spectra acquired on the biomass, classification by Soft Independent Modeling of Class Analogy (SIMCA) was employed to conduct qualitative classification of cornstover fractions, and partial least square (PLS) regression was used for quantitative chemical composition analysis. SIMCA was successfully demonstrated in classifying botanical fractions of cornstover. The developed PLS model yielded root mean square error of prediction (RMSEP %w/w) of 0.92, 1.03, 0.17, 0.27, 0.21, 1.12, and 0.57 for glucan, xylan, galactan, arabinan, mannan, lignin, and ash, respectively. The results showed the potential of FT-NIR techniques in combination with multivariate analysis to be utilized by biomass feedstock suppliers, bioethanol manufacturers, and bio-power producers in order to better manage bioenergy feedstocks and enhance bioconversion.     

Lysophosphatidic Acid Acyltransferase from Coconut Endosperm Mediates the Insertion of Laurate at the sn-2 Position of Triacylglycerols in Lauric Rapeseed Oil and Can Increase Total Laurate Levels

Expression of a California bay laurel (Umbellularia californica) 12:0-acyl-carrier protein thioesterase, bay thioesterase (BTE), in developing seeds of oilseed rape (Brassica napus) led to the production of oils containing up to 50% laurate. In these BTE oils, laurate is found almost exclusively at the sn-1 and sn-3 positions of the triacylglycerols (T.A. Voelker, T.R. Hayes, A.C. Cranmer, H.M. Davies [1996] Plant J 9: 229–241). Coexpression of a coconut (Cocos nucifera) 12:0-coenzyme A-preferring lysophosphatitic acid acyltransferase (D.S. Knutzon, K.D. Lardizabal, J.S. Nelsen, J.L. Bleibaum, H.M. Davies, J.G. Metz [1995] Plant Physiol 109: 999–1006) in BTE oilseed rape seeds facilitates efficient laurate deposition at the sn-2 position, resulting in the acccumulation of trilaurin. The introduction of the coconut protein into BTE oilseed rape lines with laurate above 50 mol % further increases total laurate levels.     

Effect of population size on the estimation of QTL: a test using resistance to barley stripe rust

The limited population sizes used in many quantitative trait locus (QTL) detection experiments can lead to underestimation of QTL number, overestimation of QTL effects, and failure to quantify QTL interactions. We used the barley/barley stripe rust pathosystem to evaluate the effect of population size on the estimation of QTL parameters. We generated a large (n=409) population of doubled haploid lines derived from the cross of two inbred lines, BCD47 and Baronesse. This population was evaluated for barley stripe rust severity in the Toluca Valley, Mexico, and in Washington State, USA, under field conditions. BCD47 was the principal donor of resistance QTL alleles, but the susceptible parent also contributed some resistance alleles. The major QTL, located on the long arm of chromosome 4H, close to the Mlo gene, accounted for up to 34% of the phenotypic variance. Subpopulations of different sizes were generated using three methods—resampling, selective genotyping, and selective phenotyping—to evaluate the effect of population size on the estimation of QTL parameters. In all cases, the number of QTL detected increased with population size. QTL with large effects were detected even in small populations, but QTL with small effects were detected only by increasing population size. Selective genotyping and/or selective phenotyping approaches could be effective strategies for reducing the costs associated with conducting QTL analysis in large populations. The method of choice will depend on the relative costs of genotyping versus phenotyping. Electronic Supplementary Material Supplementary material is available for this article at