Mapping of magnesium and of different protein fragments in sea urchin teeth via secondary ion mass spectroscopy

Mature portions of sea urchin are comprised of a complex array of reinforcing elements yet are single crystals of high and very high Mg calcite. How a relatively poor structural material (calcite) can produce mechanically competent structures is of great interest. In teeth of the sea urchin Lytechinus variegatus, we recorded high-resolution secondary ion mass spectrometry (SIMS) maps of Mg, Ca ,and specific amino acid fragments of mineral-related proteins including aspartic acid (Asp). SIMS revealed strong colocalization of Asp residues with very high Mg. Demineralized specimens showed serine localization on membranes between crystal elements and reduced Mg and aspartic acid signals, further emphasizing colocalization of very high Mg with ready soluble Asp-rich protein(s). The association of Asp with nonequilibrium, very high magnesium calcite provides insight to the makeup of the macromolecules involved in the growth of two different composition calcites and the fundamental process of biomineralization.     

Characterization and catabolism of rat very high density lipoproteins

A previously unrecognized lipoprotein of very high density was isolated from rat serum. During zonal ultracentrifugation of whole serum or of fractions from Sepharose 4B chromatography, a peak comigrating with a peak of cholesterol was found between the typical high density lipoproteins and the residual serum proteins. Centrifugation of chylomicrons, very low density lipoproteins, and high density lipoproteins, radio-iodinated in their lipid and protein moieties and mixed with serum, did not yield this peak. The pooled fractions contained about 85% protein. The remainder was lipid comprising cholesteryl esters, free cholesterol, triglycerides, phosphatidylcholine, and sphingomyelin. Polyacrylamide gel electrophoresis revealed bands in the region of apolipoproteins E and C as the major components. The composition suggested a lipoprotein, and this was substantiated by electron microscopy which showed particles with a mean diameter of 150 A. Their average hydrated density was 1.23 g/ml and the apparent molecular weight was 1.35 X 10(6). These very high density lipoproteins are characterized by a rapid catabolism as compared to high density lipoproteins. Within 10 min, 84% and 70% of intravenously injected 125I-labeled very high density lipoproteins were removed from plasma of male and female rats, respectively, and did not appear to be converted to lipoproteins of a different density class. Ninety-five percent of the removed 125I was recovered in the liver and the radioactivity per gram of tissue was also highest for the liver. Accordingly, the rate of clearance of 125I-labeled very high density lipoproteins was markedly reduced in functionally eviscerated rats. Radioautography revealed that most of the silver grains representing very high density lipoproteins were associated with hepatocytes and only about 1% was found over v. Kupffer cells. Uptake and degradation by freshly isolated rat hepatocytes were mediated by a saturable and specific binding site. Composition and metabolic pathway are compatible with a function of very high density lipoproteins in the transport of protein and lipids to the liver.     

Interpreting Upland Rice Yield and Pratylenchus zeae Relationships: Correspondence Analyses

Correspondence analyses were used to explore the relationships between yield and populations of Pratylenchus zeae in an upland rice field and in a greenhouse experiment. Initial soil (Pi) and final root (Pf) population densities of P. zeae, and yield (Y) of rice cv. UPL Ri5 were determined at 490 spots in the field. Very low Y was linked to very high Pf. Low Y was linked to medium or high Pi and medium Pf. Medium to very high Y were clustered with undetectable Pi and very low or high Pf. All yield levels were independent of very high Pi. In the greenhouse experiment where seven nematode inoculum levels and three fertilizer levels were evaluated, low Y was associated with medium or high Pf and high Y with high or low Pf. The analyses indicated that nematode-yield interaction involved a complex, dynamic process, in which the root-carrying capacity probably was a determining factor. Correspondence analysis, which does not require assumptions on the shape of nematode population-yield relationships or on variable distributions, revealed meaningful associations in these complex data sets.     

Evaluation of resistance to different insecticides in field strains of Helicoverpa armigera (Lepidoptera: Noctuidae) in Punjab, Pakistan

Susceptibility of field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) from Punjab, Pakistan to selected insecticides was evaluated using the leaf dip method. The resistance factors varied between populations. The general trends were low to moderate resistance to endosulfan; very low to low resistance to chlorpyrifos and profenofos; very low resistance to spinosad, indoxacarb and thiodicarb; moderate to high resistance to bifenthrin; high to very high resistance to cypermethrin; and very high resistance to lambda-cyhalothrin. Integrated pest management strategies aimed at reducing pesticide application, such as rotating the conventional insecticides having low resistance with newly developed synthetic insecticides and conserving natural enemies, are recommended.     

Chemical characterization of the serum very low density and high density lipoproteins from bullfrog, Rana catesbeiana.

The chemical properties of very low density and high density lipoproteins of adult bullfrog serum were determined. This serum contained extremely low levels of both very low density lipoprotein (10-30 mg/100 ml) and high density lipoprotein (5-10 mg/100 ml). The constituents of very low density lipoprotein, on a weight percentage basis, were found to be 48.1% triglyceride, 17.3% cholesterol ester, 8.8% cholesterol, 11.6% phospholipid, and 12% protein. These constituents were also present in high density lipoprotein with weight percentage values of 3.7%, 19.3%, 11.9%, 25.2%, and 36.8%, respectively. The fatty acid compositions of the triglycerides, cholesterol esters, and phosphatidylcholine were quite similar in the very low density lipoprotein and high density lipoprotein. However, shingomyelin fatty acid composition was appreciably different in the two lipoproteins. Disc gel electrophoresis in sodium dodecyl sulfate-polyacrylamide gels produced patterns with one major (approximate molecular weight, 7,000) and several minor bands for the apoprotein of very low density lipoprotein and one major (approximate molecular weight, 28,000) and several minor bands for that of high density lipoprotein.     

Vasopressin analogs with high and specific antidiuretic activity

A systematic approach to structure-activity studies is described. Its application to the vasopressin field made possible the preparation of vasopressin analogs with very high and very specific antidiuretic activity, analogs with increased pressor specificity, and analogs with high agonistic-antagonistic properties.     

Pituitary adenoma showing intermittent secretion of high molecular weight adrenocorticotropin without evidence of Cushing's disease

A 29-year-old woman was admitted in March 1998 due to high plasma ACTH levels, amenorrhea and uncontrolled diabetes mellitus (DM) which had persisted since 1991. Plasma ACTH levels showed a wide range of changes: they were usually high (59-240 pg/ml), intermittently very high (336-942 pg/ml), and sometimes normal or low. Plasma cortisol levels were usually normal but were sometimes high when the ACTH levels were very high. However, even when the plasma ACTH levels were very high, she did not show any cushingoid features. DM was diagnosed as non-insulin-dependent DM. Plasma ACTH showed an excessive response to CRH, while cortisol showed a delayed response. Plasma cortisol showed a poor response to ACTH-(1-24). ACTH receptor gene analysis revealed no mutations in the ACTH receptor-coding region. MRI showed a nonenhancing mass on the left side of the pituitary. Cavernous sinus sampling showed a very high plasma ACTH level in the left cavernous sinus compared with the levels in the right cavernous sinus and peripheral blood. Sephadex G-75 gel filtration of plasma ACTH immunoreactivity in plasma obtained by cavernous sinus sampling showed mainly high molecular forms of ACTH, probably proopiomelanocortin and ACTH-beta-lipotropin. This case is a very rare form of pituitary adenoma showing intermittent secretion of high molecular ACTH unaccompanied by cushingoid features.     

Evaluation of Environmental Risk Assessment Parameters Due to Hillslope Developments in Penang Island,Malaysia

Slope failure and soil erosion due to increased development activity in hilly areas can be catastrophic and affect the environment and humans’ well-being. This article investigates the parameters that contribute to environmental risk. Nine contributing parameters were identified. Rating the risk was proposed based on the prediction of occurrences of environmental issues and were categorized from very high (5) to very low (1) with high, medium, and low in between. The assessments were reviewed and evaluated based on rating for the chosen parameters. Maps quantifying risks were developed identifying areas of environmental risk. The overall result shows that development areas PD3 of Tanjung Bungah, and PD3, PD8, and PD9 of Paya Terubong have high rating of environmental risk. No development area is classified as very high risk or very low risk. The rating can be used to develop zones of potential high risk, and from this zoning guideline the viability can be measured for any proposed development.     

The Biocultural Context of Very High Fertility among the Bekaa Bedouin

This research report explores some of the biocultural dimensions of maximum or near maximum fertility among Bedouin tribes in the Bekaa Valley, Lebanon. The Bedouin case substantiates that very high fertility (completed family size [CFS] greater than 8.0) is found among peripheral peoples in frontier situations generated by major political-economic shifts. While the Bedouin maintained high fertility (CFS > 6.5) for approximately sixty years (1899–1960), very high fertility—linked to greater historical reliance on agriculture—was of shorter duration (1934–60). Comparisons with other very high fertility populations indicate that, at the proximate level, maximum fertility is associated with early weaning, low rates of primary sterility, and high rates of marital stability. Results also point to low subadult mortality in Bedouin society. Low mortality is best attributed to the availability of modern medical care facilities and high-quality weaning foods.     

A conserved extraordinarily long serine homopolymer in Dictyostelid amoebae

Eukaryotic protein sequences often contain amino-acid homopolymers that consist of a single amino acid repeated from several to dozens of times. Some of these are functional but others may persist largely because of high expansion rates due to DNA slippage. However, very long homopolymers with over a hundred repeats are very rare. We report an extraordinarily long homopolymer consisting of 306 tandem serine repeats from the single-celled eukaryote Dictyostelium discoideum, which also has a multicellular stage. The gene has a paralog with 132 repeats and orthologs, also with high serine repeat numbers, in various other Dictyostelid species. The conserved gene structure and protein sequences suggest that the homopolymer is functional. The high codon diversity and very poor alignment of serine codons in this gene between species similarly indicate functionality. This is because the serine homopolymer is conserved despite much DNA sequence change. A survey of other very long amino-acid homopolymers in eukaryotes shows that high codon diversity is the rule, suggesting that these too may be functional.     

Trace metals in barnacles: the significance of trophic transfer

Barnacles have very high accumulated trace metal body concentrations that vary with local trace metal bioavailabilities and represent integrated measures of the supply of bioavailable metals. Pioneering work in Chinese waters in Hong Kong highlighted the potential value of barnacles (particularlyBalanus amphitrite) as trace metal biomonitors in coastal waters, identifying differences in local trace metal bioavailabilities over space and time. Work in Hong Kong has also shown that although barnacles have very high rates of trace metal uptake from solution, they also have very high trace metal assimilation efficiencies from the diet. High assimilation efficiencies coupled with high ingestion rates ensure that trophic uptake is by far the dominant trace metal uptake route in barnacles, as verified for cadmium and zinc. Kinetic modelling has shown that low efflux rate constants and high uptake rates from the diet combine to bring about accumulated trace metal concentrations in barnacles that are amongst the highest known in marine invertebrates.     

The orientation system and migration pattern of long-distance migrants: conflict between model predictions and observed patterns

The requirements of the orientation system of naïve long-distance night migrants were analysed by comparing data on Barred Warbler Sylvia nisoria , Marsh Warbler Acrocephalus palustris and Spotted Flycatcher Muscicapa striata with data from a computer model of a clock-and-compass system. These species show, respectively, a rather restricted winter distribution in East Africa, migration through a very narrow corridor in East Africa, and rather widely distributed recoveries in the Mediterranean with more concentrated recoveries south of the Sahara. For all three species, to obtain the observed concentrations either a very high directional migratory concentration was needed in computer simulations to bring the birds successfully to their wintering areas or misorientating individuals would be subjected to a very high mortality. Neither the very high directional concentration nor the high mortality amongst misorientating individuals fit the empirical data sets. On the basis of the present study, the observed patterns seem difficult to explain by a simple clock-and-compass system only, and to account for the exceptionally precise migratory routes shown in this study it is proposed that first-time migrants might be able to use landscape topography on a regional scale in combination with corrections of directional mistakes/wind displacements.     

A note on the two-factor theory with rectification as applied to alternating current stimulation

The effect of rectification and non-normal accommodation on the two-factor theory of alternating current stimulation is studied. Rectification with normal accommodation increases the required amplitude of the current, especially for high frequencies. Rectification with non-normal accommodation introduces two upper limits, one for very low and one for very high frequencies.     

The Complexing of Lysozyme with Poly C and Other homopolymers

Lysozyme forms very large complexes with poly C, in acetate buffer solutions (pH 5.4), when the ratio of lysozyme to poly C concentration is 3/2. When this is less than 3/8 there is virtually no complexing, as evidenced by the low light-scattering power of such mixtures. At such relatively high poly C concentrations, the addition of pancreatic ribonuclease causes both the intensity and dissymmetry of scattering to rise to very high values after which time the intensity falls exponentially with time and with very little change in dissymmetry. Other homopolymers also form largest complexes with lysozyme at characteristic concentration ratios.     

Individual variability and mortality required for constant final yield in simulated plant populations

When plant monocultures are sown over a wide range of densities for a given period of time, the total biomass yield increases with density at low densities and then levels off at high densities, a phenomenon called constant final yield (CFY). There are several reported cases, however, where the total yield decreases at very high densities, but the reasons for such exceptions are not known. We used a spatially explicit, individual-based “field of neighborhood” simulation model to investigate the potential roles of spatial pattern, individual variation, and competitive stress tolerance for CFY. In the model, individual plants compete asymmetrically for light when their fields overlap, and this competition decreases growth and increases mortality. We varied (1) the initial size variation, (2) the spatial pattern, and (3) ability to survive intense competition and examined the effects on the density-biomass relationship. CFY was always observed when there was high variability among individuals, but not always when variability was low. This high size variation could be the result of high initial size variability or variation in the degree of local crowding. For very different reasons, very high and very low tolerance for competition resulted in decreasing total biomass at very high densities. Our results emphasize the importance of individual variation for population processes and suggest that we should look for exceptions to CFY in homogeneous, even-aged, regularly spaced populations such as plantations.     

Activation of lipoprotein lipase by lipoprotein fractions of human serum

Triglycerides in fat emulsions are hydrolyzed by lipoprotein lipase only when they are "activated" by serum lipoproteins. The contribution of different lipoprotein fractions to hydrolysis of triglycerides in soybean oil emulsion was assessed by determining the quantity of lipoprotein fraction required to give half-maximal hydrolysis. Most of the activator property of whole serum from normolipidemic, postabsorptive subjects was in high density lipoproteins. Low density lipoproteins and serum from which all lipoprotein classes were removed had little or no activity. Also, little activator was present in guinea pig serum or in very low density poor serum from an individual with lecithin:cholesterol acyltransferase deficiency, both of which are deficient in high density lipoproteins. Human very low density lipoproteins are potent activators and are much more active than predicted from their content of high density lipoprotein-protein. Per unit weight of protein, very low density lipoproteins had 13 times the activity of high density lipoproteins. These observations suggest that one or more of the major apoproteins of very low density lipoproteins, present as a minor constituent of high density lipoproteins, may be required for the activation process.     

Very small photoluminescent gold nanoparticles for multimodality biomedical imaging

An original synthesis method based on X-ray irradiation produced gold nanoparticles (AuNPs) with two important properties for biomedical research: intense visible photoluminescence and very high accumulation in cancer cells. The nanoparticles, coated with MUA (11-mercaptoundecanoid acid), are very small (1.4 nm diameter); the above two properties are not present for even slightly larger sizes. The small MUA-AuNPs are non-cytotoxic (except for very high concentrations) and do not interfere with cancer cell proliferation. Multimodality imaging using visible light fluorescence and X-ray microscopy is demonstrated by tracing the nanoparticle-loaded tumor cells.     

Tentative localization of glutamergic and aspartergic nerve endings in brain

1. The locations of the high affinity uptakes of glutamate, aspartate and GABA were studied autoradiographically and microchemically in slices of hippocampus and septum in vitro. 2. In hippocampus the distributions of the uptake sites for glutamate and aspartate were very similar, with much higher uptake in zones containing pyramidal cell terminals than in other zones. A reciprocal distribution was found for GABA uptake, which was in agreement with that of GAD. 3. Cutting pyramidal cell axons to CAl reduced the uptake of aspartate and glutamate in the target area in CAl by 80%. 4. Autoradiographically the uptake of aspartate was very high in the dorsal part of the lateral septum, moderately high in nucleus accumbens septi and neostriatum, and very low in the medial septum. GABA uptake was lower in the medial than in the lateral septum, but very high in a narrow transitional zone and in the insula Cajella magna. 5. Transecting the axons from hippocampus and subiculum to septum, gave a 70% reduction in the uptakes of aspartate and glutamate in the lateral septum, but no reduction in the medial septum. 6. Literature data on uptake, content and release of glutamate and aspartate in nerve endings in brain are briefly reviewed.     

Factors affecting the esterification of lipoprotein cholesterol by lecithin: cholesterol acyl transferase.

Lecithin: Cholesterol Acyltransferase (LCAT) esterified relatively small amounts of cholesterol from very low density lipoproteins (VLDL), low density lipoproteins (LDL) or high density lipoproteins (HDL) in the presence of 5% human serum albumin (HSA). On the other hand, in the presence of very high density (>1.225 g/ml) plasma fraction (F-4), the enzyme esterified cholesterol from VLDL at considerably higher rates than from LDL or HDL. VLDL together with some component present in the very high density plasma fraction (F-4) may thus provide a highly efficient complex resulting in a favorable configuration of substrate lipids for the enzyme.     

Geo-environmental impact assessment of Jinshazhou area in Guangzhou City

The geo-environmental impact of anthropogenic activities in Jinshazhou area is predicted by assessing the geo-environmental problems susceptibility under the condition of nature and anthropogenic activities in the study. An evaluation factor system including natural and anthropogenic factors is setup and the principal component analysis-fuzzy comprehensive evaluation model is selected. Results are shown in four grades, including very low, low, high, and very high. Under the natural condition, the very low, low, high, and very high susceptible regions of geo-environmental problems take up 67.73%, 0.71%, 7.30%, and 24.26%, respectively. Under the condition of anthropogenic activities, the very low, low, high, and very high susceptible regions of geo-environmental problems take up 69.18%, 5.88%, 5.88%, and 19.06%, respectively. Comparing the susceptibility of geo-environmental problems under two conditions, it can be predicted that there is a greatly negative impact of anthropogenic activities in the southern surrounding region of Jinshazhou tunnel; while in the north of the study area, such as Poly West Coast, anthropogenic activities have a positive impact on geo-environment. The present distribution of geo-environmental problems has shown that the new evaluation technique system can be successfully applied to predict the urban geo-environmental impact of anthropogenic activities.