Nutrition Starvation

Morishita, M. Morimoto, E Kitamura, K. Koga, T Fukui, Y. Maekawa, H. Yamashita, I. Shimoda, C. Phosphatidylinositol 3-phosphate 5-kinase is required for the cellular response to nutritional starvation and mating pheromone signals in Schizosaccharomyces pombe. Genes Cells, 7, 199-215 (2002)... 

The widespread notion that what we eat affects how we think has been difficult to prove. Even for the most flagrant example of poor nutrition, starvation in Third World countries, such a precept has not been indisputably demonstrated. 

Figure 8.2 Mechanism of ferritin degradation and iron release. The degradation of ferritin nanocage probably occurs lysosomal and/or proteasomal. Ferritin basal turnover, iron chelation and nutrition starvation stimulates ferritin degradation through the lysosomal pathways. While ferroportin overexpression, aging and oxidative stress causes ferritin degradation via proteasome-mediated pathways. Once iron is released from the ferritin nanocage, it will used for various metabolic processes.

The purpose of providing food is to feed the population. Previous concerns for world starvation have been abated in view of recent trends, albeit that pockets of starvation and inadequate nutrition exist. Increasing population without increasing food availability can lead to starvation or inadequate nutrition. 

A knowledge of normal metabohsm is essential for an understanding of abnormalities underlying disease. Normal metabolism includes adaptation to periods of starvation, exercise, pregnancy, and lactation. Abnormal metabolism may result from nutritional deficiency, enzyme deficiency, abnormal secretion of hormones, or the actions of drugs and toxins. An important example of a metabolic disease is diabetes mellitus. 

Our studies of the ERT cell cycles show that they are regulated by nutrition (Britton Edgar 1998). If the newly hatched larva is starved for dietary amino acids, DNA replication in most ERTs is not initiated. Under starvation conditions these tissues express low levels of cyclin E and E2F, the transcription factor which is probably responsible for cyclin E expression. If either E2F or cyclin E is induced in starved larvae, DNA replication in the ERTs is activated, and thus expression of these genes appears to limit the ERT cell cycle. When nutrient-deprived larvae are fed, expression of E2F and cyclin E mRNAs increases approximately sixfold, and DNA replication is initiated in most ERT cells. If the animal is first fed and then starved, the ERT cell cycle is activated and then inactivated quite rapidly. These experiments all indicate that the ERT cell cycle is nutrition-responsive, rather than controlled by a rigid developmental program. 

Kurland, C.G. and R. Mikkola (1993), The impact of nutritional state on the microevolution of ribosomes. In S. Kjelleberg (ed.), Starvation in Bacteria, Plenum Press, New York and London, pp. 225-237. 

From "Carnegie Nutrition Laboratory Experiment," Chap. 3 in Ancel Keys, etal., Biology of Human Starvation, University of Minnesota Press, Minneapolis, Minn., 1950, Vol. I, pp. 3462. 

The health of the small intestine can also be compromised by poor nutrition or starvation, which can regularly occur in hospital. Patients are normally starved overnight, prior to operation, and starvation may continue well after completion of the surgery because of the nature of the operation or because of the anorexia that can result from surgery or anaesthesia. This will deny adequate nutrition to epithelial cells in the intestine, which can resnlt in slow recovery after surgery and, in addition, may compromise the immune system. Provision of food by the enteral ronte, as soon as possible after injury, surgery, sepsis or bums, is therefore highly desirable (Chapter 18). 

A detailed study of the problems caused by starvation, the response to ref ceding and the best methods for refeeding was carried out by an international team of medical and nutritional experts whose Hndings were published in 1948 by The Netherlands Government (Burger et al., 1948). 

Starvation may be associated with an increase in the permeabflity of the blood-brain barrier (Hawkins 1986, as cited in Dybing and Spderlund 1999). Tissue antioxidant status may be compromised under nutritional deficiencies and starvation (Godin and Wohaieb 1988, as cited in Dybing and Spderlund 1999). 

The administration of metabolizable vegetable oils as concentrated sources of nutrition has proved to be valuable for patients who are debilitated and who are unable to take nourishment orally. In addition, oils such as soy bean oil provide a source of essential fatty acids which can be rapidly depleted in a patient after starvation for only a few days. Wretlind and his colleagues devised the phospholipids-stabilized soy oil emulsion now marketed as Intralipid (Pharmacia, now Pfizer, New York, NY) in Sweden during the 1960s and this product has been modified to carry oil-soluble drugs such as diazepam. In Europe this is marketed as Diazemuls and it may be anticipated that other drugs may be presented in the same or similar vehicles. 

Francois B, Colomb V, Bonnefont JP, Goulet O, Benhariz M, Vassault A, Rabier D, Ricour C (1997) Tolerance to starvation in children on long-term total parenteral nutrition. Clin Nutr 16 113-117... 

One example of the adaptation of bacteria to an unfavourable environment is their response to amino acid starvation. In an environment rich in amino acids, cells do not produce enzymes of amino acid synthesis. However, in the case of a nutritional downshift in the environment, cells must use their own proteins as sources of amino acids for building enzymes required for amino acid biosynthesis pathways (Gottesman and Maurizi, 2001). 

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