Local recognition of histocompatibility differences in skin grafts

Studies in rabbits of skin grafts tagged with tritiated thymidine indicate a greater proliferation of endothelial cells and fibroblasts at the site of an allograft than at that of an autograft as early as the first day after grafting. It appears, therefore, that allogeneic differences can be recognized and responded to locally almost at once. Labeled nuclear material is found to be transferred from the epithelial cells of skin grafts to host cells of the adjacent tissues. A mechanism therefore exists which might effect a local transfer of information on histocompatibility differences.     

Rates of evolution in ancient DNA from Adélie penguins

Well-preserved subfossil bones of Adélie penguins, Pygoscelis adeliae, underlie existing and abandoned nesting colonies in Antarctica. These bones, dating back to more than 7000 years before the present, harbor some of the best-preserved ancient DNA yet discovered. From 96 radiocarbon-aged bones, we report large numbers of mitochondrial haplotypes, some of which appear to be extinct, given the 380 living birds sampled. We demonstrate DNA sequence evolution through time and estimate the rate of evolution of the hypervariable region I using a Markov chain Monte Carlo integration and a least-squares regression analysis. Our calculated rates of evolution are approximately two to seven times higher than previous indirect phylogenetic estimates.     

Carbon functionalities in amber

High-resolution nuclear magnetic resonance spectra of the carbon nuclei in powdered amber, obtained by using the techniques of magic angle spinning and cross polarization, provide detailed information about the types of carbon functionalities. The entire spectrum of Baltic amber (succinite) is identical for several samples. Baltic amber shows minor differences from Sicilian amber and drastic differences from Burmese, Romanian, and Bohemian ambers.     

Crystallographic evidence for a free silylium ion

Evidence for a three-coordinate silyl cation is provided by the crystal structure of [(Mes)3Si][H-CB11Me5Br6].C6H6 (where Mes is 2,4,6-trimethylphenyl). Free (Mes)3Si+ cations are well separated from the carborane anions and benzene solvate molecules. Ortho-methyl groups of the mesityl substituents shield the silicon atom from the close approach of nucleophiles, while remaining innocent as significant ligands themselves. The silicon center is three-coordinate and planar. The downfield 29Si nuclear magnetic resonance chemical shift in the solid state (226.7 parts per million) is almost identical to that in benzene solution and in "gas phase" calculations, indicating that three-coordination can be preserved in all phases.     

THE EFFECT OF RELATING APPLICATIONS OF NITROGEN TO THE STAGE OF DEVELOPMENT OF COCKSFOOT (DACTYLIS GLOMERATA L.) GROWN FOR PRODUCTION OF SEED

An experiment is described in which nitrogen was applied in relation to the physiological stage of development in cocksfoot grown for seed. All applications of N increased the yield of seed, but applying all the N during the phase of autumnal tillering was less effective than applying it at stages of development in spring (beginning of vernal growth, initiation of inflorescences, complete differentiation of inflorescences), or in autumn and spring, because of a decrease in the number of tillers which survived to flower in the following year. Differences due to the stage of development at which N was applied in spring were small. Primary effects of N were to increase the number of tillers and ears per plant, and to accelerate the rate of development of inflorescences; in addition, N advanced the date of initiation of inflorescences without similarly advancing the date of complete differentiation of inflorescences. It is concluded that a long period between the initiation and complete differentiation of the inflorescence is conducive to high yields of seed.     

Soil morphology,depth and grapevine root frequency influence microbial communities in a Pinot noir vineyard

The composition of microbial communities responds to soil resource availability, and has been shown to vary with increasing depth in the soil profile. Soil microorganisms partly rely on root-derived carbon (C) for growth and activity. Roots in woody perennial systems like vineyards have a deeper vertical distribution than grasslands and annual agriculture. Thus, we hypothesized that vineyard soil microbial communities along a vertical soil profile would differ from those observed in grassland and annual agricultural systems. In a Pinot noir vineyard, soil pits were excavated to ca. 1.6–2.5 m, and microbial community composition in ‘bulk’ (i.e., no roots) and ‘root’ (i.e., roots present) soil was described by phospholipid ester-linked fatty acids (PLFA). Utilization of soil taxonomy aided in understanding relationships between soil microbial communities, soil resources and other physical and chemical characteristics. Soil microbial communities in the Ap horizon were similar to each other, but greater variation in microbial communities was observed among the lower horizons. Soil resources (i.e., total PLFA, or labile C, soil C and nitrogen, and exchangeable potassium) were enriched in the surface horizons and significantly explained the distribution of soil microbial communities with depth. Soil chemical properties represented the secondary gradient explaining the differentiation between microbial communities in the B-horizons from the C-horizons. Relative abundance of Gram-positive bacteria and actinomycetes did not vary with depth, but were enriched in ‘root’ vs. ‘bulk’ soils. Fungal biomarkers increased with increasing depth in ‘root’ soils, differing from previous studies in grasslands and annual agricultural systems. This was dependent on the deep distribution of roots in the vineyard soil profile, suggesting that the distinct pattern in PLFA biomarkers may have been strongly affected by C derived from the grapevine roots. Gram-negative bacteria did not increase in concert with fungal abundance, suggesting that acidic pHs in lower soil horizons may have discouraged their growth. These results emphasize the importance of considering soil morphology and associated soil characteristics when investigating effects of depth and roots on soil microorganisms, and suggest that vineyard management practices and deep grapevine root distribution combine to cultivate a unique microbial community in these soil profiles.     

Wheat bran oil and its fractions inhibit human colon cancer cell growth and intestinal tumorigenesis in Apc(min/+) mice

This study was designed to investigate the cancer preventive activities of wheat bran (WB) oil. We studied the colon cancer preventive effects of WB oil and its subfractions in the Apc(min/+) mouse model, a recognized mouse model for human colorectal cancer, and used human colon cancer cell lines (HCT-116 and HT-29) to identify possible active fractions in WB oil. Our results showed that the oil fraction of WB was more active than the water fraction against the growth of human colon cancer cell lines and that 2% WB oil significantly inhibited the overall tumorigenesis by 35.7% (p < 0.0001) in the Apc(min/+) mouse model. The WB oil was further fractioned into nonpolar lipids and phytochemicals and the phytochemical fraction was fractionated into phytosterols and phytosterol ferulates, 5-alk(en)ylresorcinols, and unidentified constituents by normal phase silica gel column chromatography. Results on cell culture showed that the phytochemical fraction had a higher inhibitory effect on HCT-116 human colon cancer cells than that of WB oil, whereas the nonpolar lipid fraction had less growth inhibitory effectiveness. However, neither fractions showed a stronger inhibition than WB oil in the Apc(min/+) mouse model. The current results demonstrate, for the first time, the intestinal cancer preventive activity of WB oil. The active ingredients, however, remain to be identified.     

Production performance and plasma metabolite concentrations of broiler chickens fed low crude protein diets differing in Thr and Gly

The aim of the study was to test the interaction between Thr and Gly in low crude protein (CP) diets in 7 to 28 d broilers on production performance and plasma metabolites. A total of 2,040 broilers were allocated to 17 treatments. A positive control (PC) diet (20.5% CP) was formulated to be adequate in dietary Thr and Gly. A negative control (NC) diet (18.5% CP, deficient in Thr and Gly) was supplemented with crystalline l-Thr and Gly to obtain a 4 Thr × 4 Gly design. Dietary Thr was tested at an apparent faecal digestibility (AFD) Thr-to-Lys ratio, which was 55%, 58%, 61% or 64%, and dietary Gly was tested at an AFD (Gly + Ser)-to-Lys ratio, which was 135%, 142%, 149% or 156%. Plasma samples were collected at 28 d. The low CP diet, formulated at 64% Thr and 156% Gly, resulted in a higher body weight gain (BWG) (P < 0.01) and similar feed conversion ratio (FCR) as the high CP treatment (PC). FCR was improved (P < 0.001) by l-Thr supplementation. Quadratic response to dietary Thr was significant for feed intake (FI), BWG and FCR (P < 0.01). A near-significant interaction for Thr × Gly was observed for FI and BWG (P_linear = 0.091 and P = 0.074, respectively). Gly did not affect production performance. An interaction between Thr × Gly on plasma free AA level was observed (P < 0.05). Free AA concentration in plasma linearly decreased with increase in AFD Thr-to-Lys ratio, and increased with increase in AFD (Gly + Ser)-to-Lys ratio. Plasma uric acid concentration was higher in PC than in all of the other diets, and plasma triglyceride concentration was decreased by l-Thr supplementation, but not by Gly. In conclusion, Gly was not limiting for growth at low dietary CP level unless Thr was deficient, showing that adequate amounts of Thr in broiler diets can overcome marginal supply of Gly and Ser and allow reduction of dietary CP from 20.5% to 18.5% for broilers from 7 to 28 d of age.     

Soil alkalinization and salinization in the djajerud Basin,Iran

The Djajerud Basin is located on the southern slopes of the Elburz Mountains, to the east of Tehran. Near its source, as the River is fed mainly by the melting of the winter snow and flows over tuffs and schists, its carbonate-enriched water can induce soil alkalinization. The Djajerud River runs from its source across a gypsum and marl piedmont. Gypsum is dissolved and modifies the chemical quality of the waters, which lose their alkaline character and get more salty. These sulphate-rich flows are less damaging because soil degradation hazards in the region are related more to salinization than to alkalinization. The Djajerud River waters next seep deep into a permeable deposition fan and feed water-tables which merge into the groundwaters of the Varamin Plain (which are also fed by chloride-rich waters from other sources). The chemical character of the Djajerud-River changes in this section, developing a marked sodium chloride salinity. The soils in this part of the Basin, due to the high groundwater salinity, have poor drainage which prevents any agriculture. The River eventually flows into the highly saline endorrheic Daryachehnamak Lake. The concept of residual alkalinity is used to examine the chemical composition of the Djajerud River along its course and affords the determination of the soil degradation hazard in the various parts of the Basin.