Nonlinearity in biology, toxicology, medicine最新文献

{"title":"Whole-range assessment: a simple method for analysing allelopathic dose-response data.","authors":"Min An,&nbsp;J E Pratley,&nbsp;T Haig,&nbsp;D L Liu","doi":"10.2201/nonlin.003.02.006","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.006","url":null,"abstract":"<p><p>Based on the typical biological responses of an organism to allelochemicals (hormesis), concepts of whole-range assessment and inhibition index were developed for improved analysis of allelopathic data. Examples of their application are presented using data drawn from the literature. The method is concise and comprehensive, and makes data grouping and multiple comparisons simple, logical, and possible. It improves data interpretation, enhances research outcomes, and is a statistically efficient summary of the plant response profiles.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"245-59"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9295532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical modelling of dose-response relationship (hormesis) in allelopathy and its application.","authors":"Min An","doi":"10.2201/nonlin.003.02.001","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.001","url":null,"abstract":"Allelopathy arises from the release of chemicals by one plant species that affect other species in its vicinity, usually to their detriment. It has been demonstrated, in plant communities, to be a factor of ecological significance by influencing plant succession, dominance, climax formation, species diversity, structure of plant communities and productivity (Whittaker and Feeney, 1971; Rice, 1984; Chou, 1989). In agroecosystems, allelopathic effects between living weeds and crops, crops in mixtures, plant straw residue and succeeding crops during decomposition of residue are also well documented (Putnam, 1978; Rice, 1984). \u0000 \u0000This phenomenon has been observed for over 2000 years. Reports as early as 300 BC document that many crop plants (eg., chick pea, barley, bitter vetch) destroyed weeds and inhibited the growth of other crop plants. The soil sickness problem in agriculture was specifically related to exudates of crop plants (Rice, 1984). However, intensive scientific research on this phenomenon only started on 20th century. The term allelopathy was first introduced by a German scientist Molisch in 1937 to include both harmful and beneficial biochemical interactions between all types of plants including microorganisms. Rice (1984) reinforced this definition in the first monograph on allelopathy. Contemporary researchers have broadened the context of allelopathy to include interactions between plants and higher animals, and have suggested that allelopathy may be part of a whole network of chemical communication between plants, and between plants and other organisms, including bacteria, yeasts, insects and mammals, and that such communication may contribute to plant defence (Harborne, 1987; Lovett and Ryuntyu, 1992; Einhellig, 1995; Siemens et al., 2002). \u0000 \u0000Chemicals that impose allelopathic influences are called allelochemicals or allelochemics (Putnam and Tang, 1986). They may be largely classified as secondary plant metabolites, which are generally considered to be those compounds (such as alkaloids, isoprenoids, phenolics, flavonoids, terpenoids, and glucosinolates etc.) which do not play a role in primary metabolic processes essential for a plant’s survival, and are produced as offshoots of primary metabolic pathways. In contrast to primary metabolism, which comprises several hundreds of low molecular weight compounds, tens of thousands of secondary substances are known today, but only a limited number have been implicated as allelochemicals (Rice, 1984). Allelochemics are present in virtually all plant tissues, including leaves, flowers, fruits, stems, roots, rhizomes, seeds and pollen. They may be released from plants into the environment by means of four ecological processes: volatilisation, leaching, root exudation, and decomposition of plant residues. Several chemicals can be released together and may exert toxicities in an additive or synergistic manner (Putnam and Tang, 1986). \u0000 \u0000During the last two decades, the science of allelopat","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"153-72"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9295530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the effect of density-dependent chemical interference upon seed germination.","authors":"Aki Sinkkonen","doi":"10.2201/nonlin.003.02.004","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.004","url":null,"abstract":"<p><p>A mathematical model is presented to estimate the effects of phytochemicals on seed germination. According to the model, phytochemicals tend to prevent germination at low seed densities. The model predicts that at high seed densities they may increase the probability of seed germination and the number of germinating seeds. Hence, the effects are reminiscent of the density-dependent effects of allelochemicals on plant growth, but the involved variables are germination probability and seedling number. The results imply that it should be possible to bypass inhibitory effects of allelopathy in certain agricultural practices and to increase the efficiency of nature conservation in several plant communities.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"225-33"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9347998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Modelling of Allelopathy: IV. Assessment of Contributions of Competition and Allelopathy to Interference by Barley.","authors":"De Li Liu,&nbsp;Min An,&nbsp;I R Johnson,&nbsp;J V Lovett","doi":"10.2201/nonlin.003.02.003","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.003","url":null,"abstract":"<p><p>One of the main challenges to the research on allelopathy is technically the separation of allelopathic effect from competition, and quantitatively, the assessment of the contribution of each component to overall interference. A simple mathematical model is proposed to calculate the contribution of allelopathy and competition to interference. As an example of applying the quantitative model to interference by barley (Hordeum vulgare cv. Triumph), the approach used was an addition of allelopathic effect, by an equivalent amount, to the environment of the test plant (white mustard, Sinapis alba), rather than elimination of competition. Experiments were conducted in glasshouse to determine the magnitude of the contributions of allelopathy and competition to interference by barley. The leachates of living barley roots significantly reduced the total dry weight of white mustard. The model involved the calculation of adjusted densities to an equivalent basis for modelling the contribution of allelopathy and competition to total interference. The results showed that allelopathy contributed 40%, 37% and 43% to interference by barley at 6, 12 and 18 white mustard pot(-1). The consistency in magnitude of the calculated contribution of allelopathic effect by barley across various densities of receiver plant suggested that the adjusted equivalent density is effective and that the model is able to assess the contribution of each component of interference regardless of the density of receiver plant.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"213-24"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9347995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementation of card: curve-fitting allelochemical response data.","authors":"De Li Liu,&nbsp;Min An","doi":"10.2201/nonlin.003.02.005","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.005","url":null,"abstract":"<p><p>Bioassay techniques are essential methods used to study the effects of allelochemicals on plant processes. It is often observed that the biological processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. Liu et al., (2003) developed a simple model to fit this type of allelochemical response data. Based on the model, CARD (curve-fitting allelochemical response data) was developed as a Windows based program that can be used to fit a stimulation-inhibition response data. An example of using CARD is given.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"235-44"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9347999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dose-response-a challenge for allelopathy?","authors":"Regina G Belz,&nbsp;Karl Hurle,&nbsp;Stephen O Duke","doi":"10.2201/nonlin.003.02.002","DOIUrl":"https://doi.org/10.2201/nonlin.003.02.002","url":null,"abstract":"<p><p>The response of an organism to a chemical depends, among other things, on the dose. Nonlinear dose-response relationships occur across a broad range of research fields, and are a well established tool to describe the basic mechanisms of phytotoxicity. The responses of plants to allelochemicals as biosynthesized phytotoxins, relate as well to nonlinearity and, thus, allelopathic effects can be adequately quantified by nonlinear mathematical modeling. The current paper applies the concept of nonlinearity to assorted aspects of allelopathy within several bioassays and reveals their analysis by nonlinear regression models. Procedures for a valid comparison of effective doses between different allelopathic interactions are presented for both, inhibitory and stimulatory effects. The dose-response applications measure and compare the responses produced by pure allelochemicals [scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one); DIBOA (2,4-dihydroxy-2H-1,4-benzoxaxin-3(4H)-one); BOA (benzoxazolin-2(3H)-one); MBOA (6-methoxy-benzoxazolin-2(3H)-one)], involved in allelopathy of grain crops, to demonstrate how some general principles of dose responses also relate to allelopathy. Hereupon, dose-response applications with living donor plants demonstrate the validity of these principles for density-dependent phytotoxicity of allelochemicals produced and released by living plants (Avena sativa L., Secale cereale L., Triticum L. spp.), and reveal the use of such experiments for initial considerations about basic principles of allelopathy. Results confirm that nonlinearity applies to allelopathy, and the study of allelopathic effects in dose-response experiments allows for new and challenging insights into allelopathic interactions.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 2","pages":"173-211"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.02.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9348002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hormetic influence of glucocorticoids on human memory.","authors":"Sonia J Lupien, Claudia Buss, Tania E Schramek, Francoise Maheu, Jens Pruessner","doi":"10.2201/nonlin.003.01.003","DOIUrl":"10.2201/nonlin.003.01.003","url":null,"abstract":"<p><p>In this paper, we discuss the effects of glucocorticoids on human learning and memory using the recent model of hormesis proposed by Calabrese and collaborators. Although acute increases in glucocorticoids have been shown to impair memory function in humans, other studies report no such impairments or, in contrast, beneficial effects of acute glucocorticoid increases on human memory function. We summarize these studies and assess whether the wealth of data obtained in humans with regard to the effects of acute increase of glucocorticoids on human cognition are in line with a hormetic function. We then discuss several factors that will have to be taken into account in order to confirm the presence of a hormetic function between glucocorticoids and human cognitive performance.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 1","pages":"23-56"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657840/pdf/nbtm-3-1-0023.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28080872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low dose effects in psychopharmacology: ontogenetic considerations.","authors":"Linda Patia Spear,&nbsp;Elena I Varlinskaya","doi":"10.2201/nonlin.003.01.006","DOIUrl":"https://doi.org/10.2201/nonlin.003.01.006","url":null,"abstract":"<p><p>Low doses of psychoactive drugs often elicit a behavioral profile opposite to that observed following administration of more substantial doses. Our laboratory has observed that these effects are often age-specific in rats. For instance, whereas moderate to high doses of the dopamine agonist apomorphine increase locomotion, suppressed locomotor activity is seen following low dose exposure, with this low dose effect not emerging consistently until adolescence. A somewhat earlier emergence of a low dose \"paradoxical\" effect is seen with the 5HT(1a) receptor agonist, 8-OH-DPAT, with late preweanling, but not neonatal, rats showing increases in ingestive behavior at low doses but suppression at higher doses. In contrast to these ontogenetic increases in expression of low dose drug effects, low dose facilitation of social behavior is seen following ethanol only in adolescent rats and not their mature counterparts, although suppression of social interactions at higher doses is seen at both ages. This hormesis-like low dose stimulation appears related in part to overcompensation, with brief social suppression preceding the subsequent stimulation response, and also bears a number of ontogenetic similarities to acute tolerance, a well characterized, rapidly emerging adaptation to ethanol. Implications of these and other ontogenetic findings for studies of hormesis are discussed.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 1","pages":"97-111"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.01.006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28080874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear response for neoplastic transformation following low doses of low let radiation.","authors":"J Leslie Redpath","doi":"10.2201/nonlin.003.01.007","DOIUrl":"https://doi.org/10.2201/nonlin.003.01.007","url":null,"abstract":"<p><p>There are now several independent studies that indicate that the dose-response for the endpoint of radiation-induced neoplastic transformation in vitro is non-linear for low linear energy transfer (LET) radiation. At low doses (<10 cGy) the transformation frequency drops below that seen spontaneously. Importantly, this observation has been made using fluoroscopic energy x-rays, a commonly used modality in diagnostic radiology, the practice of which is responsible for the majority of radiation exposure to the general public. Since the transformation frequency is reduced over a large dose range (0.1 to 10cGy) it is likely that multiple mechanisms are involved and that the relative contribution of these may vary with dose. These include the killing of a subpopulation of cells prone to spontaneous transformation at the lowest doses, and the induction of DNA repair at somewhat higher doses. Protective effects of low doses of low LET radiation on other cancer-relevant endpoints in vitro and in vivo have also been observed by several independent laboratories. These observations strongly suggest that the linear-nonthreshold dose-response model is unlikely to apply to the induction of cancer by low doses of low LET radiation in humans.</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 1","pages":"113-24"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.01.007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28080875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The involvement of calcium in the protective and toxic (nonlinear) responses of rodent and human astroglial cells.","authors":"N Debbie Slamon,&nbsp;Carole Mead,&nbsp;Chris Morgan,&nbsp;Andy Mitchell,&nbsp;Vic W Pentreath","doi":"10.2201/nonlin.003.01.005","DOIUrl":"https://doi.org/10.2201/nonlin.003.01.005","url":null,"abstract":"<p><p>The involvement of [Ca(2+)](i) in the reactive changes of astrocytes which accompany exposure to different chemicals were studied in cultures of C6 and 1321N1 cells. Cells were exposed to up to three serial pulses of the differentiating agent dBcAMP, which induces activation-type changes in the cells. Other cells, with or without the dBcAMP treatments, were treated with a range of concentrations of the antidepressants amitriptyline and fluoxetine and the glial toxicants acrylamide and chloroquine. In some experiments the L-type voltage calcium channel blocker Nifedipine was employed. [Ca(2+)](i) was measured in populations of the cells using Fura-2AM and a charge coupled device (CCD) camera attached to a fluorescence microscope. dBcAMP induced both dose- and time-dependent changes in [ Ca(2+)](i) with increases in both the [Ca(2+)](i) oscillations and mean [Ca(2+)](i) (e.g. in C6 cells at 18 min mean [Ca(2+)](i) was 318 +/- 20nM following the single differentiating dBcAMP pulses, 489 +/- 17nM (p < 0.001) following two serial pulses, and 275 +/- 30nM (not significant) following three pulses). Therapeutic doses of fluoxetine and amitriptyline caused increases in the calcium oscillations and the mean calcium concentrations ( maximum recorded mean increase was in the C6 cells at 10min by 0.02 muM fluoxetine when [Ca(2+)](i) was 411 +/- 35nM c.f. control 254 +/- 25nM, p = 0.01). Higher (non-therapeutic) doses of both antidepressants caused significant reductions. Chloroquine and acrylamide also caused dose-dependent bi-phasic types of alterations in [Ca(2+)](i), with significant reductions at lower, sub-cytotoxic doses followed by significant increases at higher concentrations, approaching those which cause cell damage. Nifedipine treatment caused some reductions in the dBcAMP, antidepressant or toxicant-induced calcium changes, but this substance also initiated cytotoxic alterations. The findings show that both the activation-type changes (which are frequently associated with increased protective capacities) and toxic responses of C6 and 1321N1 cells to different chemical agents are associated with dose-dependent alterations in [Ca(2+)](i).</p>","PeriodicalId":74315,"journal":{"name":"Nonlinearity in biology, toxicology, medicine","volume":"3 1","pages":"79-95"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2201/nonlin.003.01.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28080873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}