Qualitative defense

Data from all three studies show that. In all cases, the terpene chemistry of young foliage, or qualitative defenses, was the most important factor In reducing budworm success. The protein complexlng capacity, or quantitative defenses, of this tissue was not Important In reducing budworm success In any of the studies. 

Nonapparent plants were fast growing, short-lived, and occurred unpredictably in space and/or time. Thus, many of these plants would escape detection by the majority of herbivores. Because these plants allocated most of their resources to rapid growth and reproduction, they were believed to be defended by relatively low concentrations of toxic compounds that were generally effective against many herbivores but that some specialist herbivores would be able to evolve detoxification mechanisms against (and may even use the qualitative defenses as cues to locate their host). These toxic compounds such as alkaloids and terpenes were termed qualitative defenses because their potency made them effective at low concentrations qualitative defenses of the PAM are analogous to mobile defenses of the RAM. 

Feeny (12-13) proposed the term "quantitative" defenses of plants for chemicals of low toxicity, such as tannins, constituting up to 60Z of the dry weight. Qualitative defenses Include allomones of high toxicity but usually present in low concentrations In plants (14). Most qualitative defenses occur In ephemeral or unapparent plants (annuals and short-lived perennials which are widely dispersed) and are designed to Interfere with Internal metabolism of herbivores, whereas most predictable or apparent plants (trees) rely on quantitative defenses such as tannins designed to reduce digestibility (2). NPA qualifies as a... 

Based on this type of reasoning, investigators have divided defensive substances into (1) the acute toxins (qualitative defenses) that are present in very low concentrations in plant tissues and which exert their effects on herbivores by interfering with some basic metabolic process such as transmission of nervous impulses, and (2) digestibility-reducing substances (quantitative defenses) that are present in higher concentrations in plant tissues, that act in the gut of the animal to reduce its ability to utilize its food, particularly proteins, and whose effectiveness increases directly with their concentration (Cates and Rhoades, 1977 Feeny, 1970, 1976 McKey, 1974 Rhoades and Cates, 1976). Qualitative defenses... 

The proliferation of software during the 1980s, particularly in real time control and safety systems, focused attention on the need to address systematic failures since they could not necessarily be quantified. In other words while hardware failure rates were seen as a credibly predictable measure of reliability, software failure rates were generally agreed not to be predictable. It became generally accepted that it was necessary to consider qualitative defenses against systematic failures as an additional, and separate, activity to the task of predicting the probability of so-called random hardware failures. 

Since it is generally accepted that secondary plant constituents basically owe their existence to the selection by herbivores, microorganisms, etc., the dichotomy between alkaloids and tannins called for an explanation. To this end, various hypotheses were offered, which have been reviewed by Feeny (20). One was the "apparency hypothesis", which claimed that the more "apparent" or "predictable and available" plants should depend more on "quantitative" defense, i.e. tannins and other polyphenols, which were considered to be in principle non-detoxifiable. "Qualitative defense" involving smaller quantities of toxins such as alkaloids would then be the viable option for "unapparent" plants. However, these concepts have not been fully supported by observed patterns of predation. It seems that dso the postulated effects of tannins can be circumvented by various metabolic properties of the herbivore, and some tannins seem to be directly toxic to some consumers, in contrast to earlier postulates. Nonetheless, many recent studies have strengthened the view that tannins can act as strong deterrents for herbivores, perhaps because of their association with foliage of poor quality. 

While tlris qualitative technique is most commonly applied to operating process plants, it is also applicable to pilot plants, laboratories, storage facilities, or support functions. This comprehensive review is intended to complement other safety efforts and routine visual inspections. It should be treated as a cooperative effort to improve the overall safety and performance of the plant rather than as a dreaded intciference vvitli normal operations. Cooperation is essential. People tne likely to become defensive unless considerable effort is made to present the review as a benefit to each participant. 

Commensal or environmental fungi that are typically harmless can become invasive mycoses when the host immune defenses are impaired. Host immune suppression and risk for opportunistic mycoses can be broadly classified into three categories (1) quantitative or qualitative deficits in neutrophil function, (2) deficits in cell-mediated immunity, and (3) disruption of mechanical/and or microbiologic barriers. 

Figure 15 presents a qualitative comparison of different oxidation types on histidine ACW. Hence, the ACP cannot be seen to be characteristic for antioxidant defense, but more likely it is a feature of prehistory connected with the free-radical processes, reflecting the degree of oxidative stress. 

In general, risk reduction is accomplished by implementing one or more protective layers, which reduce the frequency and/or consequence of the hazard scenario. LOPA provides specific criteria and restrictions for the evaluation of protection layers, eliminating the subjectivity of qualitative methods at substantially less cost than fully quantitative techniques. LOPA is a rational, defensible methodology that allows a rapid, cost-effective means for identifying the protection layers that lower the frequency and/or the consequence of specific hazard scenarios. 

Stamp N (2003) Out of the quagmire of plant defense hypotheses. Q Rev Biol 78 23-55 Steinberg PD (1988) Effects of quantitative and qualitative variation in phenolic compounds on feeding in 3 species of marine invertebrate herbivores. J Exp Mar Biol Ecol 120 221-237 Steinberg PD, de Nys R, Kjelleberg S (2002) Chemical cues for surface colonization. J Chem Ecol 28 1935-1951... 

The pheromone of Leptocorisa chinensis illustrates the critical importance of the interplay between attractive and inhibitory chemicals [21]. Headspace extracts from males and females were qualitatively similar. From the eight compounds in headspace extracts that elicited strong antennal responses from males, four were discounted as being defensive chemicals or alarm pheromones. The remaining group of four chemicals, consisting of octanol,... 

In order to determine whether the defensive compounds of hybrids of the two Tribolium- species T.freemani and T. castaneum represent simple mixtures of the parental phenotypes, different glandular samples were compared by GC-MS [335]. Concerning the qualitative and quantitative data of the quinones,... 

Thus we feel that the effect of selection by the budworm for qualitative terpene defenses would be to produce a number of "chemical pattern phenotypes" among Individuals at a local or Intrapopulatlonal level. Chemical diversity should exist among populations as well, and this has been suggested In our work as well as by others (10,11). Such selection for... 

Induced resistance is the qualitative or quantitative enhancement of a plant s defense mechanisms against pests in response to extrinsic physical or chemical stimuli. These extrinsic stimuli are known as inducers or elicitors. 

High-level waste thus includes the concentrated wastes that arise from reprocessing of commercial or defense nuclear fuel that contain virtually all the fission products and transuranium radionuclides (except plutonium) in spent fuel. However, the definition does not mention the constituents of the waste, and it is only qualitative because concentrated is not quantified and the minimum fuel burnup that would yield high-level waste is not specified. Although the definition given above referred only to liquid (aqueous) waste, it is clear from further discussions in 10 CFR Part 50, Appendix F (AEC, 1970), that AEC intended that high-level waste also would include concentrated solid waste derived from liquid high-level waste that was suitable for permanent disposal. 

This model says nothing about what type of compounds a species should use to defend itself, such as high concentrations of polyphenolics or low concentrations of terpenes. The authors suggest that since there is little indication that quantitative/immobile and qualitative/mobile defenses differ in cost, effectiveness, or mode of action, there is little need for the model to predict classes of secondary metabolites. This model could be equally applied to invertebrates by replacing the words seaweed and herbivore with invertebrate and predator. 

Four qualitative criteria or hallmarks for judging the quality of data have been described— appropriateness, accuracy, integrity and transparency. Attentiveness to each hallmark is critical to the defensibility and credibility of exposure assessments. Thus, exposure assessment should follow the main scientific desiderata of any applied science empirical testing, data modelling, documentation and reproducibility of results, explicit reporting of assumptions, limitations and uncertainty, peer review and an open debate about underlying theories and models. Transparency is key to the success of all of these steps. 

---