Lignins

Figure 1 The lignin biosynthetic pathway. PAL, phenylalanine ammonia-lyase C4H, cinnamate-4-hydroxylase C3H, 4-coumarate-3-hydroxylase COMT, caffeic acid 3-O-methyltransferase CCoAOMT, caffeoyl-CoA 3-O-methyltransfer-ase F5H, ferulate-5-hydroxylase 4CL, hydroxycinnamate-CoA-ligase CCR, cinnamoyl-CoA-reductase CAD, cinnamyl alcohol dehydrogenase. F5H may hydroxylate coniferyl aldehyde and coniferyl alcohol with better efficiency than ferulic wood is used for fuel because the calorific value of...

Ingard In Transgenic Plant

Control of insect pests represents one of the major input costs of world agricultural production and consumes billions of dollars annually, predominantly in chemical pesticides and lost production. Insect control with pesticides is, however, becoming more problematic in both developed and third world countries. Farmers and consumers are increasingly aware of the environmental and ecological impacts of excessive pesticide use. As the target insects are repeatedly exposed to the same pesticide...

Plant Products In The Industrialized Drug Discovery Process

In order to be successful in random screening, high chemical diversity needs to be applied. During the early to mid-1990s, the interest in natural products for screening decreased because combinatorial chemistry was believed to deliver large chemical libraries with the required diversity at much lower cost and at higher speed than the traditional synthesis or natural product screening. However, although the diversity that can be generated by synthetic chemistry is broad, many natural products...

Automation For Drug Discovery

Until the mid-1990s, only a few thousand or 10,000 compounds were screened in a particular target. Today, large pharmaceutical companies or specialized drug discovery companies screen several hundred thousand compounds in a particular screening in a few days or weeks. This dramatic increase in screening capacity is due to advances in automation as well as to novel assay technologies (Table 1). The reader is also referred to specialized journals in this field such as Drug Discovery Today,...

References

Aggarwal RK, Brar DS, Khush GS. 1997. Two new genomes in the Oryza complex identified on the basis of molecular divergence analysis using total genomic DNA hybridization. Mol Gen Genet 254 1-12. Anonymous. 1994a. Assessment criteria for determining environmental safety of plants with novel traits. Directive Dir 94-08, Plant Products Division, Agriculture and Agri-Food Canada, Nepean Ontario pbo dir9408html). Anonymous. 1994b. The biology of Brassica napus L (canola rapeseed). Directive Dir....

Inhibitors of Digestion

The insect gut is the obvious target for orally acting insecticidal agents to be expressed in plants (e.g., Ref. 50). The membranes lining the gut appear to be the target for the Cry toxins and probably the Vips, through their pore-forming or lytic activities. The insect's digestive biochemistry is another target. Disruption should reduce nutrient intake, resulting in mortality or at least in slowing the growth of larvae to such an extent that they are subject to a greater degree of parasitism...

Contributions Of Weed Science To Biochemistry And Molecular Biology

It was already stated that there has been a bidirectional relationship often not realized between weed control and molecular biology and biochemistry. Most believe that the relationship has been unidirectional from biochemistry and molecular biology to the farmer. This is hardly so. The dire need for developing cost-effective chemical weed control systems has led to a vast industrial investment to find and develop selective herbicides and later T-HRCs. Virtually all herbicides marketed are the...

Sequestration

Excess heavy metal ions are removed from the cytosol by sequestration. The compartment mainly involved in this process in yeast and plant cells is the vacuole. Mediators of sequestration are transporters in the respective membrane. The actual substrates for most of these transporters are as yet unknown. 1. Roles of ABC-type Transporters in Sequestration Hmtl from S. pombe was the first gene identified that encodes a protein involved in vacuolar sequestration of heavy metals (66). Hmtl was...

Introduction

The first medicines known to man were certainly made from locally grown wild plants. The knowledge about the actions of the plants was compiled by trial and error and passed down from generation to generation orally. This kind of traditional medicine, folk medicine, is still very much applied in many developing countries simply because they cannot afford expensive Western medicines. The study of traditional medicines, used in different parts of the world, by modern pharmacological methods is...

Requirements For Plant Transformation

In general, plant transformation systems are based on the introduction of DNA into totipotent plant cells, followed by the regeneration of such cells into whole fertile plants. Two essential requirements for plant transformation are therefore an efficient method for introducing DNA into plant cells and the availability of cells or tissues that can easily and reproducibly regenerate whole plants. DNA can be introduced into isolated cells or protoplasts, ex-planted tissues, callus, or cell...

Organ Cultures

Hairy root cultures of anise (Pimpinella anisum L.) were grown in different nutrient media in darkness and under periodic light conditions (58,59). The composition of the essential oils obtained from hairy root cultures differed significantly from that of the fruits. Whereas the major components of the essential oils from the hairy root cultures were the anethole precursor (E)-epoxypseudoisoeugenyl 2-methylbutanoate, zingiberene, 3-bisabolene, geijerene, and pregeijerene, the terpene spectrum...

Transcription Factors

Transcription factors represent the final signaling elements that determine the gene expression pattern of a cell. Analysis of the A. thaliana genome using a consistent conservative threshold revealed more than 1700 putative transcription factors (41). Among the 29 classes of transcription factors, 16 appear to be unique to plants. Functional analysis by knockout techniques was found to be hampered by the frequent occurrence of functionally redundant genes. In contrast, overexpression of...

Potential Side Effects And Compensation Mechanisms Associated With Lignin Modifications

One envisaged drawback related to lignin manipulation in plants could be the potential attenuation of defense mechanisms against pathogens. Indeed, lignification is considered one of the adaptive plant responses to pathogen attacks (25). Down-regulating lignin synthesis could reduce the ability of plants to protect themselves against pests. Such a hypothesis has not yet been substantiated using the transgenic plants already obtained, but the use of chemical inhibitors of lignification resulted...

Metabolically Resistant THRCs

Many crops bearing transgenes coding for highly specific enzymes that metabolically catabolize herbicides have been generated (Cole and Rodgers, 2000). These include, for example, bromoxynil resistance crops bearing a nitrilase (Stalker et al., 1996), glufosinate resistance crops bearing an ace-tyltransferase (Vasil, 1996), 2,4-D-resisting crops bearing a highly specific soluble cytochrome P-450 monooxygenase (Streber and Willmitzer, 1989) phenmidipham-resisting crops bearing a bacterial gene...

Ggpp

Figure 8 Synthesis of secondary metabolites through the isoprenoid pathway. (41). Cholesterol synthesis in mammals requires the coordinated synthesis of HMG-CoA synthase, HGMR, and FPP synthase. However, the degrada-tive turnover of these enzymes appears to be regulated independently of each other (42). This example of the effect of multiple enzymes to change flux in different pathways of terpenoid metabolism has been demonstrated in plants where exposure to specific metabolites can alter the...

Transgenic Plants With Modified Antioxidant Enzyme Levels

Because of the involvement of AOS in a wide variety of environmental stresses, antioxidant enzymes are interesting molecular targets for the production of new plant varieties that can cope with these stresses. Several antioxidative stress enzymes have been genetically engineered into plants to assess their potential capacity for enhancing oxidative stress tolerance. The beneficial effects observed in some of these transgenic plants can lead to interesting agronomic applications. The following...

Hairy Roots In Phytoremediation And Phytomining Studies

The use of living plants to clean up polluted soils and waterways is a rapidly developing technology. Phytoremediation offers a range of advantages compared with existing remediation methods, including low cost, minimal site destruction and destabilization, low environmental impact, and favorable aesthetics. A related application of plants is phytomining. This emerging technology involves growing tolerant species on sites of mineralized soil or surface ore bodies, harvesting and drying the...

External Loop Airlift Reactor

External Air Lift Reactor

Figure 3 Mechanically driven reactors (a) stirred reactor, (b) stirred reactor with draught tube, and (c) rotating drum reactor. A, air inlet G, gas exhaust M, motor. loop), (c) airlift reactor (external loop), and (d) airlift reactor (draught tube). A, air inlet G, gas exhaust. loop), (c) airlift reactor (external loop), and (d) airlift reactor (draught tube). A, air inlet G, gas exhaust. with high turbulence. Three common airlift configurations, the internal loop airlift reactor, the external...

Info

AAII lines including the control are derived from a single Duboisia clone. bA and B denominate independent regenerants from a single hairy root line. Apart from modifiying secondary metabolite composition and content, the improvement of agronomic traits such as herbicide resistance, pest and disease resistance, and frost tolerance in Duboisia through genetic modification is also of interest. The most widely used systems for herbicide tolerance are the Roundup Ready and Liberty Link...

Seed Proteins And Functionality

Although some seeds are consumed by humans with little or no processing (e.g., boiled rice), the vast majority are processed by the food industry into a wide range of products. The ability to process seeds is determined by their functional properties, which in turn depend, to a large extent, on the seed proteins. For example, Kinsella (64) has identified 10 functional properties that are conferred by soybean proteins used in food systems solubility, water absorption and binding, viscosity,...