Chromosomal localization of mouse satellite DNA   总被引：67，自引：0，他引：67  

M L Pardue  J G Gall 《Science (New York, N.Y.)》1970,168(937):1356-1358

Hybridization of radioactive nucleic acids with the DNA of cytological preparations shows that the sequences of mouse satellite DNA are located in the centromeric heterochromatin of the mouse chromosomes. Other types of heterochromatin in the cytological preparations do not contain satellite DNA.  相似文献   

Naturally occurring antibodies reactive with sperm proteins: apparent deficiency in AIDS sera   总被引：3，自引：0，他引：3  

T C Rodman  J Laurence  F H Pruslin  N Chiorazzi  R Winston 《Science (New York, N.Y.)》1985,228(4704):1211-1215

A set of naturally occurring immunoglobulin M (IgM) antibodies that are reactive with a defined subset of proteins in the acrosomal cap region of human sperm has been identified. These antibodies are present in a broad spectrum of human sera from males and females, 1 day to 40 years of age, and are absent or markedly deficient in a large proportion of sera from individuals with the acquired immune deficiency syndrome (AIDS) or at risk for AIDS. The subset of proteins with which the IgM antibodies are reactive includes a factor (or factors) capable of inhibiting lectin-induced T-lymphocyte proliferation. The prevalence of the sperm-reactive IgM antibodies indicates that they are not elicited by sperm. Further, immunoreactivity of the sperm proteins resulting in depletion of specific circulating IgM antibodies, or other interactions between the sperm proteins and elements of the immune system, may be a factor in the suppressed state of the immune system in AIDS.  相似文献   

Earthworm indicators as tools for soil monitoring,characterization and risk assessment. An example from the national Bioindicator programme (France)     

Guénola Pérès  Franck Vandenbulcke  Muriel Guernion  Mickaël Hedde  Thierry Beguiristain  Francis Douay  Sabine Houot  Denis Piron  Antoine Richard  Antonio Bispo  Cécile Grand  Laurence Galsomies  Daniel Cluzeau 《Pedobiologia》2011

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Temporal variability of lake waters in the North Cascades mountains (Washington,U.S.A.)     

T. J. Loranger  D. F. Brakke  M. B. Bonoff  B. F. Gall 《Water, air, and soil pollution》1986,31(1-2):123-129

Five lakes in the North Cascades were sampled at regular time and depth intervals during the open water period in 1984. Surface water ANC was depressed during snowmelt and then increased as summer and fall progressed. Shallow lakes circulated completely in the fall, whereas deep lakes ( > 75 m) did not. Sulfate and N03 concentrations in the lakes increased during the snowmelt period and then decreased until iceover. No significant differences were found between surface ANC measurements during fall circulation in successive years.  相似文献   

Die Oberflächenladung der Ton-Humusfraktion aus Schwarzerden als Funktion von pH und Ca-Konzentration     

Klaus Bckenhoff  Stefan Gall  Walter R. Fischer 《植物养料与土壤学杂志》1997,160(2):341-346

Surface charge of clay-humus fractions from Chernozems as a function of pH and Ca-concentration The charge characteristics of clay-humus fractions from A-horizons of several Chernozems as a function of Ca concentration and pH of the soil solution was investigated. The surface charge was measured by titration with charge compensating polyelectrolytes; the endpoint was at zero potential. A logarithmic dependence of the surface charge [mol_c/kg] on the Ca concentration of the soil solution in the range ? 2 mmol/L was observed. The influence of pH on the surface charge was almost linear over a wide range of pH-values, the change in pH-dependent charges being most pronounced for the horizons with low Ca saturation on the exchange sites. It was also found that the competition between protons and Ca ions for the exchange sites leads to a distinct decrease of the influence of Ca concentration on the surface charge in acid environment. The reason for slaking of the soil surface and of the displacement of clay-humus particles in Chernozems could be attributed to an increase in surface charge with decreasing Ca concentrations after leaching of lime. According to the present findings the drop in mobility of the clay-humus fractions during acidification could be explained by a charge compensating effect of protons and aluminium ions.  相似文献   

Near infrared spectroscopy for cost effective screening of foliar oil characteristics in a Melaleuca cajuputi breeding population   总被引：2，自引：0，他引：2  

Schimleck LR  Doran JC  Rimbawanto A 《Journal of agricultural and food chemistry》2003,51(9):2433-2437

The identification of Melaleuca cajuputi leaf samples (trees) that demonstrate enhanced oil characteristics using near infrared (NIR) spectroscopy is described. Leaf samples from an unthinned M. cajuputi seedling seed orchard in Indonesia were collected and air-dried, and their 1,8-cineole content and oil concentrations were determined. NIR spectra of the leaves were obtained, and calibrations for 1,8-cineole content and oil concentration were developed using spectra that had been selected using spectral features; that is, no knowledge of 1,8-cineole content or oil concentration was used to select the calibration samples. The calibrations were used to predict the 1,8-cineole content and oil concentration of the remaining samples. It was demonstrated that NIR spectroscopy could be used to identify leaf samples that had high 1,8-cineole contents and oil concentrations. The technique has the potential to greatly reduce the time involved in ranking large numbers of samples for these attributes, as is a requirement in tree breeding programs to enhance oil production.  相似文献   

Integrated natural resource management: Why?     

Laurence R. Jahn 《Agriculture and Human Values》1987,4(2-3):94-99

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Physicochemical structure-activity relationship of DDT congeners and the inhibition of mitochondrial ATPase     

Curtis C. Dary  Laurence K. Cutkomp 《Pest management science》1984,15(5):443-454

Structure-activity relationships were used to determine the physicochemical properties of DDT that are important in the inhibition of oligomycin-sensitive mitochondrial ATPase activity of red coxal muscle tissue homogenates of the American cockroach (Periplaneta americana). The results were compared with structure-activity relationships derived from toxicity values for houseflies (Musca domestica) and blowflies (Phormia regina), reported in the literature. Toxicity was found to be promoted by hydrophobicity and electron donation. Toxicity was concluded to be a route of action process involving the distribution and partitioning of insecticide to active sites and apart from them. Enzyme inhibition, in contrast to factors contributing to toxicity, was determined to be a mode of action process predicted by the lipophilic parameter (π) and the steric constant, van der Waals radii (VWR), and represents action upon a sterically sensitive, hydrophobic site in the membrane sector of mitochondrial ATPase.  相似文献   

Interrelationships Among SADIE Indices for Characterizing Spatial Patterns of Organisms     

Xu X  Madden LV 《Phytopathology》2005,95(8):874-883

ABSTRACT The SADIE (spatial analysis by distance indices) methodology for data analysis is a useful approach for quantifying the patterns of organisms (in terms of patches and gaps) and testing for randomness of the patterns. We investigated the interrelationship among key SADIE indices: index for distance to regularity for a data set (I(a)), a global measure of aggregation or clustering; the local clustering indices (v(i) and v(j)), scaled distances to regularity for each individual sampling unit; and the averages of v(i) and v(j) across all sampling units, which are additional global measures of aggregation. We demonstrated that v(i) and v(j) are mathematically related to I(a) and showed conditions when I(a) and mean local clustering indices give very similar results. Overall differences in average v(i) and Iv(j) I values, and between I(a) and these averages, decreased with increasing size of the sampling grid in a simulation study. This was because one component of v(i) and v(j) (iY)-a measure of the distance to regularity under randomness for a given location (not a given count)-was found generally to vary little with location, except for locations near corners of the sampling grid. Nevertheless, because distance to regularity for individual observed counts was location-dependent, and this location effect varied with the observed counts value as well, a new-scaled index for each count x location combination may be warranted. The implications of these findings on epidemiological research are discussed.  相似文献   

Zoonotic aspects of Mycobacterium bovis and Mycobacterium avium-intracellulare complex (MAC)   总被引：4，自引：0，他引：4  

Biet F  Boschiroli ML  Thorel MF  Guilloteau LA 《Veterinary research》2005,36(3):411-436

Pathogens that are transmitted between the environment, wildlife, livestock and humans represent major challenges for the protection of human and domestic animal health, the economic sustainability of agriculture, and the conservation of wildlife. Among such pathogens, the genus Mycobacterium is well represented by M. bovis, the etiological agent of bovine tuberculosis, M. avium ssp. paratuberculosis (Map) the etiological agent of Johne disease, M. avium ssp. avium (Maa) and in a few common cases by other emergent environmental mycobacteria. Epidemiologic surveys performed in Europe, North America and New Zealand have demonstrated the existence and importance of environmental and wildlife reservoirs of mycobacterial infections that limit the attempts of disease control programmes. The aim of this review is to examine the zoonotic aspects of mycobacteria transmitted from the environment and wildlife. This work is focused on the species of two main groups of mycobacteria classified as important pathogens for humans and animals: first, M. bovis, the causative agent of bovine tuberculosis, which belongs to the M. tuberculosis complex and has a broad host range including wildlife, captive wildlife, domestic livestock, non-human primates and humans; the second group examined, is the M. avium-intracellulare complex (MAC) which includes M. avium ssp. avium causing major health problems in AIDS patients and M. avium ssp. paratuberculosis the etiological agent of Johne disease in cattle and identified in patients with Crohn disease. MAC agents, in addition to a broad host range, are environmental mycobacteria found in numerous biotopes including the soil, water, aerosols, protozoa, deep litter and fresh tropical vegetation. This review examines the possible reservoirs of these pathogens in the environment and in wildlife, their role as sources of infection in humans and animals and their health impact on humans. The possibilities of control and management programmes for these mycobacterial infections are examined with regards to the importance of their natural reservoirs.  相似文献