Defense function

A patent also serves a defensive function. It provides the patentee with a partial or total shield that prevents others from patenting inventions which would ultimately restrict the patentee s commercial activity in the marketplace. 

A wide diversity of herbal remedies have purported abilities to stimulate defense functions. Complexes of carbohydrate and lignin, which are present in some herbs, modulate enteric immune functions (Kiyohara et al, 2000), and the changes in cytokine secretion (Matsumoto and Yamada, 2000) can trigger systemic responses. The polysaccharides present in other herbal medicines augment production of immunoglobulin (Ig) A by the Peyer s patches in the small intestine (Sakushima et al, 1997 Yu et al, 1998). The responses of the enteric immune system to lectins are variable (Pusztai 1993), and can elicit systemic responses (Lavelle et al, 2000). Other phytochemicals provide protection by inducing detoxification pathways in mucosal cells (Williamson et al, 1998). 

BUDDINGTON R K, KELLY-QUAGLIANA K, BUDDINGTON K K, KIMURA Y (2002b) Non-digeStible oligosaccharides and defense functions lessons learned from animal models. Br J Nutr. 87 S231-9. 

Secondary chemistry differs from primary chemistry principally in its distributional variability and it is this variability that has intrigued ecologists for the past 30 years. Theories [or provisional hypotheses (35)] to account for the structural differentiation and function of secondary metabolites, as well as the differential allocation of energy and materials to defensive chemistry, abound, but they are almost exclusively derived from studies of plant-herbivore interactions (Table 2). This emphasis may be because the function of secondary chemicals in plants is less immediately apparent to humans, who have historically consumed a broad array of plants without ill effects, so alternative explanations of their presence readily come to mind. The fact that animals upon disturbance often squirt, dribble, spray, or otherwise release noxious substances at humans and cause pain leads to readier acceptance of a defensive function [although there are skeptics who are unconvinced of a... 

Steppuhn A, Gase K, Krock B, Habtschke R, Baldwin IT (2004) Nicotine s defensive function in nature. PloS Biol 2 1074-1080... 

Kessler A, Baldwin IT (2001) Defensive function of herbivore-induced plant volatile emissions in nature. Science 291 2141-2144... 

Table 11.1 Classes of plant compound with antiherbivore defense functions...

The trans-chrysanthemic acid 88 is an essential component of naturally occurring pyrethrin esters which are present in the flower of Chrysanthenum cinera-riaefolium and has a defense function in these plants [122]. Very effective as an antifeedant for herbivores, it presents a broad spectrum as an insect repellent. 

Abstract Alkaloids are a special group of secondary compounds and are part of an organism s adaptation mechanism to its living environment. They are not toxic when stored, but become toxic as a result of cell pH change. The defensive function of alkaloids is only secondary, and connected to internal immune and regulation processes. Animal responses to alkaloids are very diverse. Some animals can tolerate alkaloids relatively well, while others are harmed or even poisoned by them. Animal behaviour in relation to alkaloids depends on evolutionary and co-evolutionary factors. Sequestration of alkaloids is connected with these processes. Alkaloids are a part of plant-derived nutrition. A selective toxicity of these compounds in vertebrates is clearly observed. Vertebrates have the capacity to recognize alkaloids. 

The sophisticated equipment required for volatile identification has long confined the topic of herbivore-induced volatiles to the laboratory, but extrafloral nectaries have traditionally been studied in the field. Moreover, the work on extrafloral nectaries has mainly addressed wild plant species within their natural habitat, whereas the study of plant volatiles has long focussed on agricultural crops. As a result, we have a relative wealth of held evidence for the defensive function of extrafloral nectaries. 

A number of studies have provided the ultimate proof for the defensive function of extrafloral nectaries by demonstrating that herbivory reduction by ants actually translates to an increased reproductive fitness of nectar-providing plants (Koptur, 1979 Rico-Gray and Thien, 1989 Oliveira, 1997 Wagner, 1997). In the most... 

In addition to these empirical studies, there is indirect ecological evidence for the defensive function of extrafloral nectaries. Several studies have reported correlations between the abundance of plants with extrafloral nectaries and ant abundance (Pemberton, 1998 Rico-Gray et al, 1998). Bentley (1977) and Rickson (1977) showed that plants may lose extrafloral nectaries in ecosystems void of mutualist ant species. 

Even though this evidence supports the defensive function of extrafloral nectaries, the evidence is largely based on myrmecophilous plants. In other plant species, the benefit of ant attendance is not always as clear (O Dowd and Catchpole, 1983 Koptur and Lawton, 1988). In these species, the provision of extrafloral nectar may serve to enhance the effectiveness of other plant-predator (Ruhren and Handel, 1999) or plant-parasitoid interactions (Lingren and Lukefahr, 1977 Bugg etal, 1989 Koptur, 1994), or serve other (non-defensive) functions. 

Gronquist M, Bezzerides A, Attygalle A, Meinwald J, Eisner M, Eisner T. 2001. Attractive and defensive functions of the ultraviolet pigments of a flower (Elypericum calycinum). Proc Natl Acad Sci USA 98 13745-13750. 

In addition to being the defining feature of collagens, the collagen triple helix is present as a motif in a variety of proteins, many of which are involved in host-defense functions (Fig. 1 Table I Kielty and Grant, 2002 Lu et al, 2002 Matsuzawa et al., 2004 Myllyharju and Kivirikko, 2004 ... 

The nasal passages have an olfactory function, but with regard to inhaled toxicants they have primarily a defensive function and form the initial defensive barrier against inhaled... 

A minor variation on this theme would be that the initial function was indeed chemical defense, but that the propionates acquired some minor secondary function that has been retained in many lineages of opisthobranchs after the defensive function was lost. The re-evolution of a defensive function would then be possible, and it would be a curious example of atavism. At any rate, the situation with respect to prostaglandins in Tethys suggests that not all apparent absence of metabolites necessarily means an inability to synthesize them. Further research as to the validity of such scenarios is obviously necessary. In particular, there are obvious opportunities for seeking propionates at lower concentrations and in as yet unexamined taxa. Other possibilities for new research include comparative biosynthesis and comparative enzymology. 

Many possible defensive functions for algal secondary metabolites have been proposed including antimicrobial, antifouling, and antifeedant activities. To date, the role of these compounds as... 

Some authors claim that liposaccharides can depress the content of TNF-a and increase the activity of superoxide dismutase (SOD) and catalase, thus—via mediators—they can affect the immune system (Can et al. 2003). It has been demonstrated that the NF-p transcription factor, (highly sensitive to the redox potential in its environment), which regulates synthesis of many mediators—cytokines, associated with inflammatory condition and the phenomenon of adhesion of cells— becomes deregulated in old age. Defense functions in such cases (and primarily in arthritis and arthritis-related conditions) are said to be performed by antioxidants (including a-lipoic acid), which can modulate the activity of monocytes and inhibit changes caused by deregulating of the transcription factor NF-kB under the influence of redox conditions in elderly people (Lee and Hughes 2002). 

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