Biochemical trait

J. H. Xia and J. K. M. Roberts, Improved cytoplasmic pH regulation, increased lactate efflux, and reduced cytoplasmic lactate levels are biochemical traits expressed in root tips of whole maize seedlings acclimated to a low-oxygen environment. P/anr P/iy.vto/. 105 651 (1994). 

Khan ZR, Pickett JA, Hassanah A, Hooper AM, Midega CAO (2008) Desmodium species and associated biochemical traits for controlhng Striga species present and future prospects. Weed Res 48 302-306... 

C. The measurable expression of the genotype as a molecular, clinical, or biochemical trait is the phenotype. 

Organisms that have a very restricted diet can be expected to have evolved more specific mechanisms to target chemicals in the diet that are especially toxic substances. Thus, an insect living on one plant might protect itself against one toxin by specific biochemical traits—see Chapter 9. 

What Do We Study When We Examine Biochemical Adaptation What Is a "Biochemical Trait" ... 

The mandatory dissection process involved in studying biochemical traits creates two primary types of problem. One problem is a general one that obtains whether or not the biochemist is interested in examining the adaptive value of a biochemical trait. This common problem relates to the difficulties that arise when data from studies of simplified systems are used to extrapolate back to the much more complex reality of the living organism in its natural habitat. Let us try to delineate this problem in some detail, so we can better appreciate the challenges we face in studying biochemical adaptation. 

A biochemist typically must dissect an organism into separate biochemical constituents in order to carry out the intended studies. For instance, through isolating and purifying one protein from among tens of thousands in the cell, detailed, closely controlled in vitro experiments can be done on this particular study system (or biochemical trait, if you will). This requirement for simplification is absolutely necessary for controlled experimentation, yet is also the source of a major philosophical problem How do we know that the properties we measure in an isolated system resemble those... 

Based on the physical and biochemical parameters and molecular techniques, traded (exported) cardamoms from India, Sri Lanka and Guatemala had been characterized (Thomas et al., 2006). Indian cardamom was found to be superior for most of the physical quality parameters and for the biochemical traits. The GC profile of the oil of Indian cardamom also indicates a high quantity of a-terpinyl acetate and 1,8-cineole, which imparts aroma and flavour to the cardamom, thus reinforcing the legendary belief of the high intrinsic quality of the Indian cardamom. The GC-MS pattern of the volatile components in the cardamom... 

This discussion is not meant to be complete, but should illustrate that a number of insect herbivores exploit the chemistry of their food plants. These insects are adapted and have evolved a number of molecular and biochemical traits that can be considered as prerequisites. However, many of the respective plant-insect interactions have not yet been studied, and... 

Phenotypes—How a gene is expressed (e.g., eye color, height, drug metabolism capacity). The expression of genetic alleles (genotype) as an observable physical or biochemical trait. 

In the search for biochemical correlates in the brain of persons with undesirable human behavior, it is important to distinguish causes from effects. We look for manifestations rather than causes. Abnormalities in brain chemistry are a state of the patient, not necessarily a biochemical trait. We look for antecedent events but do not assume that they are ultimate causes. 

Genetics of human cell lines. IV DNA mediated heritable transformation of a biochemical trait. Proc. Natl Acad. Sci. USA., 48, 2026-2034. 

In addition to selecting naturally occurring microbial cultures that possess a desired metabolic trait, it is also possible to use enrichment culture techniques to develop microbial cultures with unique biochemical traits. The substrate range of enzymes catalyzing a certain reaction can be expanded through the use of enrichment culture techniques. 

This process of evolving new biochemical traits in the laboratory can also be accelerated by the use of directed evolution. In directed evolution, the genes that encode a biochemical trait of interest are subjected to specific mutagenesis, and then enrichment culture techniques are used to isolate derivatives that contain the desired improvements. 

All the strains have a similar cellular organization, but their physiological differences account for their specific characteristics and varying impact on wine qnality. They are classified according to their morphological, genetic, and biochemical traits. 

At the same time, it should not be considered, as it sometimes is, that the cellular level of regulation is based mainly upon transcriptional events. In reality, the genetic regulation of biochemical traits on the cellular level could be realized not only through differential transcription, but also through post-transcriptional, translational, and post-translational processes. The relative significance of genetic systems in the control of these processes could differ in each particular case for the total complex of differentiation. 

What is known of the transcription process during ontogenesis allows the suggestion of the presence of temporal and spatial differences in the phenotypic expression of biochemical traits. A large amount of data, obtained mainly by electrophoretic and immunochemical methods, has confirmed this suggestion. 

The activity of either isoenzyme, naturally, depends, to a great degree, upon which variant of a given multienzyme system will be realized. Since in some cases some of the enzyme molecules cannot associate, this could occur, for instance, as a result of a lack of conformational accordance. Thus, the complex effect of differences in translation rate and also post-translational events (assembly with membranes or inhibitors, degradation, formation of multienzyme complexes, etc.) is an important factor in the realization of differential expression of biochemical traits in the phenotype. 

In the previous chapters the various degrees of phenotypic expression of maternal and paternal biochemical traits were discussed. However, extreme cases are known when one of the parental characteristics is not expressed at all. Such an extreme case of differential gene expression is allelic exclusion. In this case, one of the homologous alleles is inactivated and does not participate in the function of the gene. 

Fig. 70. Cellular (/e/jr) and tissue right) levels of the expression of biochemical traits...

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