Species definition

Changes in heart rate require correction different formulas may optimize correction in different species Definition of the end of the T wave is problematic in some species such as the dog, having a variable morphology of the T wave... 

Microwave spectra. Rotational energy levels for pyridine using isotopic species. Definition of bond lengths and angles, dipole moment... 

To study and quantify microbial diversity one has to define what a species is. This is not a trivial objective since bacteria reproduce asexually and interbreeding cannot be applied for traditional species definition. While individual species of higher organisms may differ by as little as 1 % in their respective DNA, bacterial strains differ by up to 30%. Beside the so called species problem in microbiology, it is a widely accepted concept that bacteria with 16S rRNA gene sequences with similarity more than 98.7% (checked by DNA DNA hybridisation) belong to the same species. 

Magne et al. (1974) made a somewhat similar study, but their emphasis was on the enhancement of the solubility of uranium in granites through the activity of heterotrophic bacteria. In their experiments microbial activity increased the amount of uranium in solution by factors of 2 to 97. Several organisms may have been involved. Bacillus licheniformis being the one species definitely isolated. Species of Thiobacillus were absent, so that the enhancement of solubility observed was probably quite unrelated to leaching processes depending upon the oxidation of pyrite. ... 

Within this overview of copper(I), lithium, and magnesium thiolate complexes, one of the aims is to highlight the influence that (intramolecular) nitrogen coordination exerts on the structure of such species, since intermolecular (auxiliary) coordination of heteroatoms often leads to poorly defined species. An example of this poor species definition is the reaction behavior of polymeric copper(I) thiophenolate, [Cu(SPh)]. with triphenylphosphine Several P-coordinated aggregates with variable stoichiometry were reported (Scheme 1) (27-29). This behavior makes it difficult to study one specific species in cop-per(I) thiolate catalyzed organic reactions since equilibria are likely to occur. 

If we translate tendencies to the reproductive isolation (among other aspects) then Simpson s definition broadens Mayr s definition by addition of the evolutionary aspects. Simpson s definition became know as the evolutionary species definition. 

This definition is what I calls a synthetic species definition based upon hope. I -think the majority of plant taxonomists adhere to this definition (or to a very similar one at least). Species are found via a search for resemblance that can be expressed in charactersi this definition is more operational than the previous two definitions. 

Since it is very important to know which food material is consumed in terms of regulatory issues as well as consumer awareness, a standard way of species definition at the molecular level is sought. 

Stackebrandt E, Goebel BM (1994) Taxonranic note a place fin DNA-DNA reassociatimi and 16S rRNA sequence analysis in the present species definition in bacteriology. Int J Syst Bacteiiol 44 846-849... 

Stackebrandt E, Fredeiiksen W, Garrity GM, Giimont PA, Kampfer P, Maiden MC, Nesme X, Rossello-Mma R, Swings J, Triiper HG, Vauterin L, Ward AC, Whitman WB (2002) Report of the ad hoc connnittee for the re-evaluati(Hi of the species definition in bacteriology. Int J Syst Evol Microbiol 52 1043—1047... 

Konstantinidis KT, Tiedje JM. Genomic insights that advance the species definition for prokaryotes. Proc Natl Acad Sci USA. 2005a 102 2567 72. doi 10.1073/pnas.0409727102. 

Richter M, Rossell6-M6ra R. Shifting the genomic gold standard for the prokaryotic species definition. Proc Natl Acad Sci USA. 2009 106 19126-31. doi 10.1073/pnas.0906412106. 

Wide variation in the rate of acetylation of isoniazid and of other drugs which are metabolized by acetylation is not unique to man but is observed in several other species. Definitive studies establishing that such variability is primarily the result of inherited differences between animals of a species have been carried out in only one species other than man, i.e., the rabbit (Frymoyer and Jacox, 1963a,b). Frymoyer and Jacox found that when sulfadiazine was administered to rabbits (20 mg/kg), half-life determinations of the unmetabolized drug in blood were distributed bimodally (Fig. 4) with a mean of 41 minutes for the rapid acetylator subpopulation and a mean of 89 minutes for the slow acetylator subpopulation. This difference could not be attributed to differences in volumes of distribution of unacetylated sulfadiazine, in rates of distribution of sulfadiazine to the body water, or to age or sex. Furthermore, they showed from pedigree analysis of 15 rabbit families that the pattern of inheritance of sulfadiazine metabolism in the rabbit was essentially the... 

Although elution time from a LC separation provides valuable information for a particular species, definitive identification of the lipid species has to be performed based on its product-ion mass spectrum. For those researchers who are using LC-MS for identification and quantification of lipid species, familiar with the fragmentation patterns of lipid classes, therefore deriving the product-ion mass spectra of individual lipid species, is very important although a few databases and/or libraries (see Chapter 5) can be used to aid the identification. Resolving complex biological lipids into a... 

Relation (2.1) involves the standard chemical potential p.° of a species. Definitively, it cannot be determined experimentally, nor is its chemical potential p.,-. However, we noticed when we were on the subject of mass law that a judicious linear combination of standard chemical potentials is experimentally accessible. In truth, it is impossible to know the absolute value of a chemical potential because it is a free enthalpy and because the absolute value of any free enthalpy itself cannot be known. However, the fact that an absolute value of a quantity cannot be determined is not rare. An example that is more common than those of enthalpies, free enthalpies, and free entropies is provided by an altitude point. The difference in altitude between two points is measurable. It is not the case for their absolute altitude. Numerous other quantities also follow suit. 

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