Disease relevance of Population Density

• In this study we have examined the effect of population density on the ability of 17 beta-estradiol (E2) to induce PRL mRNA, DNA synthesis, and progesterone receptor in GH4C1 pituitary tumor cells [1].
• Sucrose addition to sterile soil resulted in a 10(-3)-fold reduction of the final E. coli population density. sacB induction prevented the proliferation and triggered the rapid disappearance of E. coli from natural soil [2].
• Pyrene-amended soils, with and without inoculation with strain RJGII-135, experienced both increases and decreases in the population sizes of the inoculated strain and indigenous Mycobacterium populations during incubation [3].
• Protein deficiency impairs erythropoiesis in rats by reducing serum erythropoietin concentration and the population size of erythroid precursor cells [4].
• RA patients with active synovitis and increased 3H-TdR incorporation in the low density population of cells have higher overall 3H-TdR incorporation than normal controls and patients with inactive RA [5].

High impact information on Population Density

• Polygyny may also contribute, but the reduction of variation within populations that we measure for the Y chromosome, relative to the autosomes and mitochondrial DNA, is of such magnitude that differences in the effective population sizes of the sexes alone are insufficient to produce the observation [6].
• Mucin degradation in human colon ecosystems. Fecal population densities of mucin-degrading bacteria estimated by a "most probable number" method [7].
• The requirement of each hematopoietic sub-population for a specific sub-set of survival factors, provides a flexible mechanism for dictating the cellular composition of the mature population and for controlling population size [8].
• We show (i) that initial land degradation was caused by settlement, not by agriculture; (ii) that population density inversely correlates with erosion; and (iii) that land degradation was associated with European Conquest but not from the introduction of the Euro-agro suite [9].
• Comparisons with mtDNA ND2 sequences from some of the same individuals revealed a larger female versus male effective population size for chimpanzees [10].

Chemical compound and disease context of Population Density

• The apparent clock-like evolution of Escherichia coli in glucose-limited chemostats is reproducible at large but not at small population sizes and can be explained with Monod kinetics [11].
• Without sufficient pantothenate, the population size of Treponema R8 was limited to 40% of the total cells [12].
• Pseudomonas sp. L2 proliferated rapidly in lake water amended with glucose, phosphate, and NH4NO3, but its numbers subsequently fell abruptly; however, in water amended with cycloheximide and nystatin, which killed indigenous protozoa, the population density was higher and the fall in numbers was delayed [13].
• The diversity and population densities of facultative anaerobic bacteria with the capacity to hydrate oleic acid and linoleic acid in the rumen of sheep and dairy cows were determined [14].
• An association between Propionibacterium population size and extent of C3 cleavage was found, but Staphylococcus and Pityrosporum population sizes did not appear to have an appreciable influence [15].

Biological context of Population Density

• Acyl homoserine lactones (acyl-HSLs) are important intercellular signaling molecules used by many bacteria to monitor their population density in quorum-sensing control of gene expression [16].
• Applying ANOVA to the distributions of the allele sizes at microsatellite loci from a set of populations, grouped by repeat motif types, we estimated the effect of population size differences and mutation rate differences among loci [17].
• Amino acid substitution at the Adh locus of Drosophila is facilitated by small population size [18].
• Based on these results, we suggest that PGD2-induced programmed cell death is part of the population density regulation as observed in infected animals [19].
• OBJECTIVE: The authors conducted a pilot study to develop preliminary data on the frequency of cytochrome P450-2D6 (CYP2D6) genotypes in state psychiatric hospital patients and to establish population sizes needed to determine potential clinical relevance in therapeutic outcome [20].

Anatomical context of Population Density

• Given the high population density of mucosal IgA plasma cells and the enormous surface area of pIgR-expressing mucosal epithelium, it is likely that significant local transcytosis of IgA ICs occurs in vivo [21].
• Among mature T lymphocytes, the NF-kappaB/Rel transcription factors are coupled to receptors that control cell population sizes by concurrently regulating survival and multiplication [22].
• Thus, wt-APC, by progressively decreasing survivin and increasing apoptosis from crypt bottom to top, may limit the population size of stem cells and other proliferative cells in the lower crypt; mutant APC may allow expansion of these populations, thereby initiating tumorigenesis [23].
• Results indicate that for B cells the control of the population size by T3R alpha 1 and T3R alpha 2 is intrinsic [24].
• A strong correlation between CD4 and CD8 population densities and macrophages with the other subpopulations was noticed [25].

Associations of Population Density with chemical compounds

• We find that the physical layout of nodes form a fractal set, determined by population density patterns around the globe [26].
• Under the conditions of high population density and low calf serum concentration used in the assay for transformed focus formation, the transformed or neoplastic cells were much more sensitive to killing by methotrexate (MTX) than were non-neoplastic cells in the same culture [27].
• During the deceleratory phase, the equilibrium growth rate of C6 cells is a monotonically decreasing function of population density at all observable densities, whether sub- or supraconfluent [28].
• The epidermis on the backs or ears of DBA/2 mice treated for 7 days with a 20% concentration of monobenzyl ether of hydroquinone (MBEH) had a significantly greater population density of ATPase- and Ia-positive cells compared with control mice treated with diluent [29].
• In a group of hypercholesterolemic patients (n = 19), high density lipoprotein cholesterol levels were negatively correlated to the population size of CD64-CD16+ monocytes [30].

Gene context of Population Density

• This was evidenced by the ability of all but the smallest population-size treatments to maintain relatively high levels of mean fitness even under the 100-fold increase in mutational pressure caused by knocking out the msh-2 gene [31].
• These results suggest that CD4-CD8-CD44+ IL-2R+ thymocytes express Fas and there is overpopulation of the subsequent developmental stage of thymocytes in Fas mutant lpr mice [32].
• Based on the relative decrease in the number of CFU-GM in the op/op mice, it appears that the population size of these progenitors is less dependent on CSF-1 than the hematopoietic stem cell population size as evidenced by the day-11 CFU-S assay [33].
• The contribution of BRCA1 and BRCA2 mutations in breast cancer populations, unselected for age and family history, has been examined in several studies reporting mutation frequencies between 1% and 12% by screening methods, population sizes, and to what extent the gene/s were screened differed in the studies [34].
• It was shown that the constitutive acid phosphatase (PHO3 gene product) is mainly transported to the cell surface by a lower density population of vesicles, while the repressible acid phosphatase (a heteromer encoded by PHO5, PHO10, and PHO11 genes) by a vesicle population of higher density [35].

Analytical, diagnostic and therapeutic context of Population Density

• Since the latter two quantities depend on the sample size, theta is often used as a measure of the amount of DNA polymorphism, where theta = 4Nmu, N is the effective population size and mu is the neutral mutation rate per site per generation [36].
• The influence of male parr body size and mate competition on fertilization success and effective population size in Atlantic salmon [37].
• Immunocytochemistry with antisera against the calcium-binding proteins calbindin D-28k and parvalbumin was used to assess population densities and mosaics [38].
• AAO population sizes were estimated by competitive PCR targeting the gene amoA, and correlated significantly with nitrate concentration [39].
• Soil bacterial population densities increased within 24 hours after treatment between 4-fold (Magic Wet) and 19-fold (Chitosan) [40].

References