Genomics-Based Discovery of Plant Genes for Synthetic Biology of Terpenoid Fragrances: A Case Study in Sandalwood oil Biosynthesis.

Terpenoid fragrances are powerful mediators of ecological interactions in nature and have a long history of traditional and modern industrial applications. Plants produce a great diversity of fragrant terpenoid metabolites, which make them a superb source of biosynthetic genes and enzymes. Advances in fragrance gene discovery have enabled new approaches in synthetic biology of high-value speciality molecules toward applications in the fragrance and flavor, food and beverage, cosmetics, and other industries. Rapid developments in transcriptome and genome sequencing of nonmodel plant species have accelerated the discovery of fragrance biosynthetic pathways. In parallel, advances in metabolic engineering of microbial and plant systems have established platforms for synthetic biology applications of some of the thousands of plant genes that underlie fragrance diversity. While many fragrance molecules (eg, simple monoterpenes) are abundant in readily renewable plant materials, some highly valuable fragrant terpenoids (eg, santalols, ambroxides) are rare in nature and interesting targets for synthetic biology. As a representative example for genomics/transcriptomics enabled gene and enzyme discovery, we describe a strategy used successfully for elucidation of a complete fragrance biosynthetic pathway in sandalwood (Santalum album) and its reconstruction in yeast (Saccharomyces cerevisiae). We address questions related to the discovery of specific genes within large gene families and recovery of rare gene transcripts that are selectively expressed in recalcitrant tissues. To substantiate the validity of the approaches, we describe the combination of methods used in the gene and enzyme discovery of a cytochrome P450 in the fragrant heartwood of tropical sandalwood, responsible for the fragrance defining, final step in the biosynthesis of (Z)-santalols.

The effect of treatment on mental and psychomotor development of marasmic infants according to age of admission.

The mental and psychomotor development of severely malnourished infants were examined during nutritional and psychological treatment. There was a significant difference between younger and older infants in their response to the treatment. The older infants had a remarkable reduction of their psychomotor development at admission and showed a considerable recovery throughout treatment. The younger infants became more affected during hospitalisation. The bodyweight deficit had mostly recovered by the end of the treatment.

Long-term effects of early undernutrition and environmental stimulation on learning performance of adult rats.

Early undernutrition was achieved in rats by increasing litter size; the undernourished groups were reared from birth to 21 days in litters of 18 pups per dam and the control groups in litters of six pups per dam. Each of these groups was divided at weaning into two sub-groups: previously undernourished, stimulated (PUS+) and non-stimulated (PUS-); and control, stimulated (CS+) and non-stimulated (CS-). From weaning, all animals were fed ad libitum. Environmental manipulation began at weaning and lasted 11 weeks. "Stimulated" rats were maintained in colonies of three per cage, were handled for 5 minutes each day and allowed to explore a "stimulation chamber" for 30 minutes. All groups were tested in a Hebb-Williams maze at 100 approximately 10 days of age. The nutritional treatment did not impair Hebb-Williams performance, and environmental stimulation improved the learning performance both in control and previously undernourished groups. Neither nutritional nor stimulation treatment affected intraproblem learning. Total DNA and cholesterol were reduced in forebrain and cerebellum in undernourished rats. Brain stem was the region of the CNS least affected by early undernutrition. Environmental manipulation did not modify neurochemical parameters.

Psychomotor development during treatment of severely marasmic infants.

Previous studies of amlnourished infants have shown that their psychomotor development improves parallel to their nutritional rehabilitation. The present study showed that our patients recovered weight-for-age faster than height-for-age, becoming 42% obese at the end of the treatment. The psychomotor development was also significantly improved, but mainly in social, language and fine coordination areas. The gross motor behaviour did not show any improvement during 5 months of treatment. These results are interpreted in terms of the syndrome of dissociation of maturation.

Effects of chlordiazepoxide on maze performance of rats subjected to undernutrition in early life.

The purpose of this research was to study the isolated effects of and interactions between undernutrition and emotional reactivity upon maze performance in rats. This work compares the effects of chlordiazepoxide on learning performance in two groups of adult rats: one undernourished early in life and then rehabilitated, and the other normally nourished. Chlordiazepoxide was used at 5 mg/kg body weight administered i.p. 30 min before each test. The response was evaluated in a Hebb-Williams maze. Water was used as reinforcement. Chlordiazepoxide improved performance in the early undernourished group 197 +/- 55.9 errors to 149 +/- 33.6 (mean +/- SD). Chlordiazepoxide impaired performance of the normal group from 107 +/- 22.7 errors to 197 +/- 42.2 errors. Analysis of variance gave an F = 6.64, which is significant (P less than 0.01). This supports the hypothesis that the high emotional level of previously undernourished subjects acts negatively upon problem-solving performance.

Plasma lecithin: cholesterol acyltransferase activity in normal full-term newborn infants.

Plasma lecithin: cholesterol acyltransferase (LCAT) activity was studied in 100 normal full-term newborn infants during the first few days of life. The present study shows that plasma LCAT activity present at birth-though at much lower levels than those in the maternal blood-undergoes a fall after birth followed by a rise. It is also shown that the activity of the plasma LCAT enzyme is not strictly linked to the esterification of plasma-free cholesterol in the first three days after birth. However, from the fourth day onwards, there was a good correlation between LCAT activity and esterification of plasma-free cholesterol. The results suggest that plasma LCAT in newborn infants could be partially derived from maternal sources.