Competitive interactions

Apart from the use of venoms, which are normally general-purpose defense secretions, several species of ants have been shown to use specific secretions to compete with particular species. Examples are only likely to arise from field studies, or laboratory studies conducted in semi-natural conditions, and this phenomenon is, therefore, not particularly well documented. 

A number of small, mass-recruiting species of ants are able to repel larger species by means of glandular secretions. Monomoriumpharaonis, Solenopsis fugax (HOlldobler, 1973) and M. minimum (Adams and Traniello, 1981) use 

The chemical nature of the Harpagoxenus substances is unknown, but the main components from Formica pergandei and F. subintegra are decyl, dodecyl and tetradecyl acetates. These substances originate in the hypertrophied 

Dufour s gland, and are discharged in such quantities that the workers of the slave species are disoriented and unable to organize a defense of their brood (Regnier and Wilson, 1971). 

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The effect of a nonradioactive ligand [B] displacing a radioligand [A ] by a competitive interaction is shown schematically as... 

Lans, M.C., Klasson-Wehler, E., and Willemsen, M. et al. (1993). Structure-dependant competitive interaction of hydroxy-PCB, PCDD, and PCDE with transthyretin. Chemico-Biological Interactions 88, 7-21. 

For simple competitive interaction at a single class of site, a plot of log (Z /(B0 - / ,)) vs. log[I] will be linear with a slope of -1 and intercept on the x-axis of log (IC50). This estimate of IC50 can be... 

The effects of organic molecules and phosphate on the adsorption of acid phosphatase on various minerals, and kaolinite in particular, have been investigated by Huang et al. [97]. The Langmuir affinity constant for AcP adsorption by kaolinite follows the series tartrate (K — 97.8) > phosphate (K= 48.6) > oxalate (K — 35.6) > acetate (K= 13.4). At low concentration, acetate even promoted the adsorption of acid phosphatase. It was considered that competitive interactions between anionic adsorbates can occur directly through competition for surface sites and indirectly through effects of anion adsorption on the surface charge and protonation. 

The weaker delocalization in the latter case would be expected from the anticooperative nature of competitive interactions with two donors.) These interactions thus exhibit forms and magnitudes that are generally similar to those found in smaller boron hydrides. 

The enantioselective hydrogenation of ketones which have two heteroatoms on both sides of the carbonyl group tends to give lower enantioselectivity due to the competitive interaction of the functionalities with the catalyst. The extent depends... 

Sunda, W. G. and Huntsman, S. A. (1983). Effect of competitive interactions between manganese and copper on cellular manganese and growth in estuarine and oceanic species of the diatom Thalassiosira, Limnol. Oceanogr., 28, 924-934. 

Neurotoxins, such as saxitoxin and anatoxin-a, have been implicated in mediating competitive interactions between toxic cyanobacteria and other photoautotrophs, but few studies have explicitly examined the allelopathic effects of these compounds (e g., Kearns and Hunter 2001). Although it is reasonable to assume that these compounds bind to algal and cyanobacterial sodium channels in a similar fashion as in vertebrate neurons, support for this hypothesis is currently lacking. 

These are mobile phase additives (usually amines), which by competitive interaction, block the detrimental effect of silanol groups. As noted in a previous review [4],... 

Meerts lA, van Zanden JJ, Luijks EA, van Leeuwen-Bol I, Marsh G, Jakobsson E, Bergman A, Brouwer A (2000) Potent competitive interaction of some brominated flame retardants and related compounds with human transthyretin in vitro. Toxicol Sci 56 95-104 Mengel K (1985) Dynamics and availability of major nutrients in soils. Adv Soil Sci 2 67-134 Mercer JW, Cohen RM (1990) A review of immiscible fluids in the subsurface Properties, models, characterization, and remediation. J Contam Hydrol 6 107-163 Mertens JA (2000) Trichloroethylene. In Kirk-Othmer Encyclopedia of Chemical Technology. Wiley New York. Available at http //www.mrw.interscience.wiley.com/emrw/9780471238966/ kirk/article/tricmert.aOl/current/pdf... 

Hewlett, P.S. and R.L. Placket. 1964. An unified theory for quantal responses to mixtures of drugs Competitive interactions. Biometrics 20 566-575. 

Geelhoed, J.S. Hiemstra.T. Van Riemsdijk, WH. (1998) Competitive interaction between phosphate and citrate on goethite. Environ. Sci.Techn. 32 2119-2123 Gehring, A.U. Hofmeister, A.M. (1994) The transformation of lepidocrodte during heating a magnetic and spectroscopic study. 

H2-antagonists competitively interact with the H2-receptor. They are very specific for the H2-sub-type of the histamine receptor. 

Meerts lA, van Zanden JJ, Luijks EA, et al. 2000. Potent competitive interactions of some brominated flame retardants and related compounds with human transthyretin in vitro. Toxicol Sci 56(1) 95-104. 

By means of an apparent Michaelis constant (A mapp) together with a maximum rate ( max) of butadiene metabolism both obtained with human liver microsomes (Filser et al., 1992), Filser et al. (1993) constructed a human model which was later extended by Csanady et al. (1996) for the butadiene metabolites epoxybutene and diepoxybutane. For butadiene and epoxybutane, the required human tissue air partition coefficients were measured using autopsy material (Table 23). Filser et al. (1993) investigated the influence of styrene co-exposure on butadiene metabolism by assuming competitive interaction. Simulations for a 70-kg man exposed over 8 h to 5 or 15 ppm [11 or 33 mg/m3] butadiene indicated total amounts of butadiene metabolized of 0.095 and 0.285 mmol, respectively, reduced by about 19% and 37% as a result of co-exposure to 20 and 50 ppm styrene, respectively. No influence of butadiene on styrene metabolism was noted. 

In related work, Martiney et al. showed that metalloporphyrins with zinc or tin were capable of inhibiting hemozoin formation in trophozoite extracts [105]. Zn(II) and Sn(IV) analogs of heme were selected for study as a result of their known competitive interactions with heme in a number of systems and their use as pharmacological photosensitizers. The order of efficacy for these metalloporphyrins was ZnDPIX>SnPPIX ZnPPIX. This order is consistent with the proposed... 

Abidi and Mounts separated the molecular species of the neutral phospholipids PC and PE using A/M/W (70/22/8) containing tetra-alkyl ammonium phosphates (TAAPs). The competitive interaction of TAAPs and analyte solutes with the reversed-phase HPLC column resulted in... 

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