scholarly journals Coexistence of “Cream Skimmer” and “Crumb Picker” Phenotypes in Nature and in Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Nancy Huntly ◽  
Audrey R. Freischel ◽  
Anna K. Miller ◽  
Mark C. Lloyd ◽  
David Basanta ◽  
...  
Keyword(s):  
Resource Availability ◽  
Cell Types ◽  
Variance Partitioning ◽  
The Other ◽  
Common Mechanism ◽  
Glut 1 ◽  
Pulsed Resources ◽  
Ca Ix ◽  
Trade Offs ◽  
Over 40 Years

Over 40 years ago, seminal papers by Armstrong and McGehee and by Levins showed that temporal fluctuations in resource availability could permit coexistence of two species on a single resource. Such coexistence results from non-linearities or non-additivities in the way resource supply translates into fitness. These reflect trade-offs where one species benefits more than the other during good periods and suffers more (or does less well) than the other during less good periods, be the periods stochastic, unstable population dynamics, or seasonal. Since, coexistence based on fluctuating conditions has been explored under the guises of “grazers” and “diggers,” variance partitioning, relative non-linearity, “opportunists” and “gleaners,” and as the storage effect. Here we focus on two phenotypes, “cream skimmers” and “crumb pickers,” the former having the advantage in richer times and the latter in less rich times. In nature, richer and poorer times, with regular or stochastic appearances, are the norm and occur on many time scales. Fluctuations among richer and poorer times also appear to be the norm in cancer ecosystems. Within tumors, nutrient availability, oxygen, and pH can fluctuate stochastically or periodically, with swings occurring over seconds to minutes to hours. Despite interest in tumor heterogeneity and how it promotes the coexistence of different cancer cell types, the effects of fluctuating resource availability have not been explored for cancer. Here, in the context of pulsed resources, we (1) develop models of foraging consumers who experience pulsed resources to examine four types of trade-offs that can promote coexistence of phenotypes that do relatively better in richer versus in poorer times, (2) establish that conditions in tumors are conducive for this mechanism, (3) propose and empirically explore biomarkers indicative of the two phenotypes (HIF-1, GLUT-1, CA IX, CA XII), and (4) and compare cream skimmer and crumb picker biology and ecology in nature and cancer to provide cross-disciplinary insights into this interesting, and, we argue, likely very common, mechanism of coexistence.

scholarly journals Phenology of two interdependent traits in migratory birds in response to climate change

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150288 ◽  
Author(s):  
Nadiah Pardede Kristensen ◽  
Jacob Johansson ◽  
Jörgen Ripa ◽  
Niclas Jonzén
Keyword(s):  
Climate Change ◽  
Resource Availability ◽  
Migratory Birds ◽  
Egg Laying ◽  
The Other ◽  
Sufficient Evidence ◽  
Hatching Date ◽  
Arrival Date ◽  
Body Of Knowledge ◽  
Asynchronous Hatching

In migratory birds, arrival date and hatching date are two key phenological markers that have responded to global warming. A body of knowledge exists relating these traits to evolutionary pressures. In this study, we formalize this knowledge into general mathematical assumptions, and use them in an ecoevolutionary model. In contrast to previous models, this study novelty accounts for both traits—arrival date and hatching date—and the interdependence between them, revealing when one, the other or both will respond to climate. For all models sharing the assumptions, the following phenological responses will occur. First, if the nestling-prey peak is late enough, hatching is synchronous with, and arrival date evolves independently of, prey phenology. Second, when resource availability constrains the length of the pre-laying period, hatching is adaptively asynchronous with prey phenology. Predictions for both traits compare well with empirical observations. In response to advancing prey phenology, arrival date may advance, remain unchanged, or even become delayed; the latter occurring when egg-laying resources are only available relatively late in the season. The model shows that asynchronous hatching and unresponsive arrival date are not sufficient evidence that phenological adaptation is constrained. The work provides a framework for exploring microevolution of interdependent phenological traits.

scholarly journals Amino acid transport in normal and glutathione-deficient sheep erythrocytes

1976 ◽  
Vol 154 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J D Young ◽  
J C Ellory ◽  
E M Tucker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Cell Types ◽  
The Other ◽  
Acid Transport ◽  
Sheep Erythrocytes ◽  
Uptake Rates

1. Uptake rates for 23 amino acids were measured for both normal (high-GSH) and GSH-deficient (low-GSH) erythrocytes from Finnish Landrace sheep. 2. Compared with high-GSH cells, low-GSH cells had a markedly diminished permeability to D-alanine, L-alanine, α-amino-n-butyrate, valine, cysteine, serine, threonine, asparagine, lysine and ornithine. Smaller differences were observed for glycine and proline, whereas uptake of the other amino acids was not significantly different in the two cell types.

scholarly journals Multiple actins in drosophila melanogaster

1979 ◽  
Vol 82 (1) ◽  
pp. 86-92 ◽  
Author(s):  
SJ Horovitch ◽  
RV Storti ◽  
A Rich ◽  
ML Pardue
Keyword(s):  
Body Wall ◽  
Flight Muscle ◽  
Cell Types ◽  
Major Product ◽  
The Other ◽  
Stable Form ◽  
Larval Body ◽  
Drosophila Cell ◽  
Muscle Tissues ◽  
Adult Abdomen

The tissue and developmental specificities of the three Drosophila isoactins, originally identified in primary myogenic cultures and in the permanent Schneider L-2 cell line, have been investigated. Of these three isoactins (I, II, and III), actins I and II are stable and actin III is unstable. Two-dimensional polyacrylamide gel electrophoretic analyses of total cellular extracts after 1-h [(35)S]methionine pulses were performed on a large variety of embryonic, larval, and adult muscle and nonmuscle tissues. The results suggest that isoactins II and III are generalized cellular actins found in all drosophila cell types. Actin I, on the other hand, is muscle-associated and is found exclusively in supercontractile muscle (such as larval body wall and larval and adult viscera) including primary myogenic cell cultures. Although actin I synthesis is not detectable during very early embryogenesis, it is detectable by 25 h and actin I is a major stable actin in all larval muscle tissues. Actin I is synthesized in reduced amounts relative to the other actins in late third instar larvae but is again a major product of actin synthesis in the adult abdomen. A stable actin species with the same pI as actin III has been identified in the adult thorax and appears to be unique to flight muscle tissue. This new stable form of thoracic actin may be the result of a stabilization of the actin III found in other tissues or may be an entirely separate gene product.

The effect of pancreatic mesenchyme on the differentiation of endocrine cells from gastric endoderm

Development ◽  
1987 ◽  
Vol 100 (4) ◽  
pp. 661-671 ◽  
Author(s):  
B. Kramer ◽  
A. Andrew ◽  
B.B. Rawdon ◽  
P. Becker
Keyword(s):  
Endocrine Cell ◽  
Endocrine Cells ◽  
Cell Types ◽  
The Other ◽  
Chick Embryos ◽  
Cell Type ◽  
Pancreatic Insulin ◽  
Somatostatin Cells ◽  
Regional Specificity ◽  
Gut Endocrine Cells

To determine whether mesenchyme plays a part in the differentiation of gut endocrine cells, proventricular endoderm from 4- to 5-day chick or quail embryos was associated with mesenchyme from the dorsal pancreatic bud of chick embryos of the same age. The combinations were grown on the chorioallantoic membranes of host chick embryos until they reached a total incubation age of 21 days. Proventricular or pancreatic endoderm of the appropriate age and species reassociated with its own mesenchyme provided the controls. Morphogenesis in the experimental grafts corresponded closely to that in proventricular controls, i.e. the pancreatic mesenchyme supported the development of proventricular glands from proventricular endoderm. Insulin, glucagon and somatostatin cells and cells with pancreatic polypeptide-like immunoreactivity differentiated in the pancreatic controls. The latter three endocrine cell types, together with neurotensin and bombesin/gastrin-releasing polypeptide (GRP) cells, developed in proventricular controls and experimental grafts. The proportions of the major types common to proventriculus and pancreas (somatostatin and glucagon cells) were in general similar when experimental grafts were compared with proventricular controls but different when experimental and pancreatic control grafts were compared. Hence pancreatic mesenchyme did not materially affect the proportions of these three cell types in experimental grafts, induced no specific pancreatic (insulin) cell type and allowed the differentiation of the characteristic proventricular endocrine cell types, neurotensin and bombesin/GRP cells. However, an important finding was a significant reduction in the proportion of bombesin/GRP cells, attributable in part to a decrease in their number and in part to an increase in the numbers of endocrine cells of the other types. This indicates that mesenchyme may well play a part in determining the regional specificity of populations of gut endocrine cells.

Chemotaxis-associated properties of separated prestalk and prespore cells of Dictyostelium discoideum

1986 ◽  
Vol 64 (8) ◽  
pp. 722-732 ◽  
Author(s):  
J. D. Mee ◽  
D. M. Tortolo ◽  
M. B. Coukell
Keyword(s):  
Light Scattering ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Binding Sites ◽  
Large Fraction ◽  
Cell Types ◽  
The Other ◽  
Deficient Mutant ◽  
Camp Phosphodiesterase ◽  
Intracellular Cgmp

During development, prestalk and prespore cells of Dictyostelium discoideum become organized in multicellular structures. This physical association makes it difficult to characterize the two cell types biochemically and physiologically. In the present study, we have separated prestalk and prespore cells from 16-h slugs by the method of Tsang and Bradbury and have examined a number of chemotaxis-associated properties of these cells. When assayed on phosphate-buffered agar under both gradient and nongradient conditions, isolated prestalk cells responded chemotactically to cAMP and, unexpectedly, to folate and certain folate derivatives. In contrast, separated prespore cells failed to respond appreciably to any of these compounds. Neither prestalk nor prespore cells of strain HC91 exhibited a cAMP-induced increase in intracellular cGMP. However, a cGMP response was observed in both prestalk and prespore cells of strain NP368, a cGMP phosphodiesterase deficient mutant. Both cell types exhibited comparable cAMP-mediated light-scattering changes and possessed similar levels of surface cAMP- and folate-binding sites. On the other hand, prestalk cells had at least fourfold higher cAMP phosphodiesterase and folate deaminase activities than prespore cells, and a large fraction of both activities was on the cell surface. Therefore, the greater chemotactic response of prestalk cells to cAMP and folate on agar might be due, in part, to their increased capacity to generate a chemoattractant gradient. Results obtained in this study demonstrate that prestalk and prespore cells separated by this procedure can be used in certain physiological as well as biochemical experiments.

scholarly journals A new uncertainty estimation approach with multiple datasets and implementation for various precipitation products

2020 ◽  
Vol 24 (4) ◽  
pp. 2061-2081 ◽  
Author(s):  
Xudong Zhou ◽  
Jan Polcher ◽  
Tao Yang ◽  
Ching-Sheng Huang
Keyword(s):  
Spatial Heterogeneity ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Variance Partitioning ◽  
Uncertainty Estimation ◽  
The Other ◽  
New Approach ◽  
Multiple Datasets ◽  
Uncertainty Estimates ◽  
Spatiotemporal Scales

Abstract. Ensemble estimates based on multiple datasets are frequently applied once many datasets are available for the same climatic variable. An uncertainty estimate based on the difference between the ensemble datasets is always provided along with the ensemble mean estimate to show to what extent the ensemble members are consistent with each other. However, one fundamental flaw of classic uncertainty estimates is that only the uncertainty in one dimension (either the temporal variability or the spatial heterogeneity) can be considered, whereas the variation along the other dimension is dismissed due to limitations in algorithms for classic uncertainty estimates, resulting in an incomplete assessment of the uncertainties. This study introduces a three-dimensional variance partitioning approach and proposes a new uncertainty estimation (Ue) that includes the data uncertainties in both spatiotemporal scales. The new approach avoids pre-averaging in either of the spatiotemporal dimensions and, as a result, the Ue estimate is around 20 % higher than the classic uncertainty metrics. The deviation of Ue from the classic metrics is apparent for regions with strong spatial heterogeneity and where the variations significantly differ in temporal and spatial scales. This shows that classic metrics underestimate the uncertainty through averaging, which means a loss of information in the variations across spatiotemporal scales. Decomposing the formula for Ue shows that Ue has integrated four different variations across the ensemble dataset members, while only two of the components are represented in the classic uncertainty estimates. This analysis of the decomposition explains the correlation as well as the differences between the newly proposed Ue and the two classic uncertainty metrics. The new approach is implemented and analysed with multiple precipitation products of different types (e.g. gauge-based products, merged products and GCMs) which contain different sources of uncertainties with different magnitudes. Ue of the gauge-based precipitation products is the smallest, while Ue of the other products is generally larger because other uncertainty sources are included and the constraints of the observations are not as strong as in gauge-based products. This new three-dimensional approach is flexible in its structure and particularly suitable for a comprehensive assessment of multiple datasets over large regions within any given period.

scholarly journals Phenotype of recovering lymphoid cell populations after marrow transplantation.

1985 ◽  
Vol 161 (6) ◽  
pp. 1483-1502 ◽  
Author(s):  
K A Ault ◽  
J H Antin ◽  
D Ginsburg ◽  
S H Orkin ◽  
J M Rappeport ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Nk Cells ◽  
Cell Types ◽  
Lymphoid Cells ◽  
The Other ◽  
Hla Dr ◽  
T Cell Antigens ◽  
Leu 7

Four patients who received bone marrow transplants were studied sequentially during the posttransplant period to define the pattern of recovering lymphoid cell types. Three patients received T cell-depleted, HLA-matched marrow, and one received untreated marrow from an identical twin. Blood lymphoid cells were labeled with 25 different pairs of monoclonal antibodies. In each sample, one antibody was conjugated to fluorescein and one to phycoerythrin, thus allowing simultaneous assessment of the expression of the two markers using the fluorescence activated cell sorter. A total of 14 antibodies were used, routinely including HLE, Leu-M3, Leu-4, Leu-1, Leu-5, Leu-9, Leu-6, Leu-2, Leu-3, HLA-DR, Leu-7, Leu-11, Leu-15, and Leu-12. Other antibodies were used to further define some populations. This study has allowed us to define six distinct cell types that have appeared in all four patients by day 90 posttransplantation, and which account for 90-100% of all circulating lymphoid cells. These cell types are (a) T helper cells expressing Leu-1, Leu-4, Leu-9, Leu-5, Leu-3, and variable amounts of HLA-DR; (b) T suppressor cells expressing Leu-1, Leu-4, Leu-9, Leu-5, Leu-2, and variable amounts of HLA-DR; (c) B cells expressing Leu-12, B1, HLA-DR, IgD, and IgM, but none of the T cell antigens; (d) an unusual B cell phenotype (Leu-1 B) expressing all of the B cell markers, and also having low amounts of Leu-1, but none of the other T cell antigens; (e) natural killer (NK) cells expressing Leu-11, Leu-15, Leu-5 but none of the other T cell or B cell markers; (f) NK cells expressing Leu-11, Leu-15, Leu-5, and low levels of Leu-2. Both NK types also express Leu-7 on some, but not all cells. The relative frequencies of these cell types varied among the patients and with time, but the striking findings were the presence of relatively few mature T cells, large numbers of NK cells, and the preponderance of the unusual Leu-1 B cell over conventional B cells in all three patients who developed B cells. Sorting experiments confirmed the NK activity of the major NK cell phenotypes, and DNA analysis confirmed that all of the cells studied were of donor origin. In addition, analysis of Ig genes in one patient showed that the Leu-1 B cells were not clonally rearranged.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Morphological correlates of prey consumed by Podarcis melisellensis (Braun, 1877) and P. siculus (Rafinesque, 1810) (Sauria, Lacertidae) from two mainland regions in the eastern Adriatic area

2013 ◽  
Vol 65 (3) ◽  
pp. 1015-1025
Author(s):  
S.Z. Stamenkovic ◽  
Rada Matic
Keyword(s):  
Resource Availability ◽  
Optimal Foraging ◽  
Morphological Traits ◽  
Prey Size ◽  
Morphological Characteristics ◽  
Optimal Foraging Theory ◽  
Variance Partitioning ◽  
Morphometric Data ◽  
Lizard Species ◽  
Trophic Resource

The correlation between trophic utilization and morphology was studied for two lizard species (Podarcis melisellensis and P. siculus) from two mainland localities in the eastern Adriatic area; this is the first report of trophic and morphometric data for P. melisellensis from mainland populations. Variance partitioning showed that most of the variation in morphological traits for the analyzed lizards was the result of differences between species, and to a lesser extent between sexes. Locality did not have a strong effect on the variation of morphological traits. Prey weight is the only characteristic of prey that generally exhibits correlations with morphological characteristics rather than prey size. The pattern of correlations is generally weaker for P. melisellensis than for P. siculus. Optimal foraging theory predictions were generally confirmed: P. siculus is more constrained by trophic resource availability, with a premium on larger and heavier prey consumed in the less productive locality (SM), which can be relaxed in more productive regions (KL). P. melisellensis shows such constraints only for males in the less productive region (SM). Females of both species consume heavier prey.

scholarly journals Application of Stem Cell-Derived Extracellular Vesicles as an Innovative Theranostics in Microbial Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Hani Keshavarz Alikhani ◽  
Bahare Shokoohian ◽  
Sama Rezasoltani ◽  
Nikoo Hossein-khannazer ◽  
Abbas Yadegar ◽  
...  
Keyword(s):  
Stem Cell ◽  
Infectious Diseases ◽  
Extracellular Vesicles ◽  
Cell Types ◽  
The Other ◽  
Microbial Pathogens ◽  
Microbial Diseases ◽  
Clinical Complications ◽  
Set Up ◽  
Novel Therapeutic Strategies

Extracellular vesicles (EVs), as nano-/micro-scale vehicles, are membranous particles containing various cargoes including peptides, proteins, different types of RNAs and other nucleic acids, and lipids. These vesicles are produced by all cell types, in which stem cells are a potent source for them. Stem cell-derived EVs could be promising platforms for treatment of infectious diseases and early diagnosis. Infectious diseases are responsible for more than 11 million deaths annually. Highly transmissible nature of some microbes, such as newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), drives researcher’s interest to set up different strategies to develop novel therapeutic strategies. Recently, EVs-based diagnostic and therapeutic approaches have been launched and gaining momentum very fast. The efficiency of stem cell-derived EVs on treatment of clinical complications of different viruses and bacteria, such as SARS-CoV-2, hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), Staphylococcus aureus, Escherichia coli has been demonstrated. On the other hand, microbial pathogens are able to incorporate their components into their EVs. The microbe-derived EVs have different physiological and pathological impacts on the other organisms. In this review, we briefly discussed biogenesis and the fate of EVs. Then, EV-based therapy was described and recent developments in understanding the potential application of stem cell-derived EVs on pathogenic microorganisms were recapitulated. Furthermore, the mechanisms by which EVs were exploited to fight against infectious diseases were highlighted. Finally, the deriver challenges in translation of stem cell-derived EVs into the clinical arena were explored.

Constitutional History

2016 ◽  
Author(s):  
Olof Petersson
Keyword(s):  
Welfare State ◽  
General Pattern ◽  
Public Life ◽  
Constitutional Reform ◽  
The Other ◽  
Constitutional History ◽  
History Writing ◽  
Parliamentary Government ◽  
Other Hand ◽  
Trade Offs

In one sense, Sweden follows the general pattern of constitution-making. The major shifts in the constitutional history have occurred in the aftermath of great crises. Constitutions have been important as descriptions and justifications of the prevailing forces of power. On the other hand, the constitutions of Sweden have been relatively insignificant as norms regulating political and public life. Constitutions have been important as history writing but relatively unimportant as normative principles shaping society, and, indeed, profound changes such as the introduction of parliamentary government have taken place without constitutional reform. The Swedish welfare state was built upon negotiations and practical trade-offs rather than constitutional arguments.

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