Activities tubers

Tuberization in potato plants is considered to be controlled by a specific active compound. The structure of an active tuber-inducing compound from potato leaves was determined to be 3-oxo-2-(5 -3-D-glucopyranbsyloxy-2 -(E)-pentenyl)-cyclopentane-l-acetic acid. The aglycone of this glucoside is 12-OH-jasmonic acid, termed tuberonic acid [53]. Jasmonic acid, methyl jasmonate and cucurbic acid were also shown to be capable of inducing tuberization in potato in vitro [53]. In addition, jasmonic acid seems to be involved in tuberization in yam [54], Jerusalem artichoke [55] and in bulb formation of garlic [56]. 

Chirinos, R. et al., High-performance liquid chromatography with photodiode array detection (HPLC-DAD)/HPLC-mass spectrometry (MS) profiling of anthocyanins from Andean mashua tubers (Tropaeolum tuberosum Ruiz and Pavon) and their contribution to the overall antioxidant activity, J. Agric. Food Chem., 54, 7089, 2006. 

PL activity in extracts from tuber tissue of potatoes transformed with the plasmids pB33-PL3 and p35S-PL3. 

The effect of endogenous PL3 (A) and externally applied E. carotovora enzymes (B) on the cell viability of tuber tissue disks from PL-inactive (I) and PL-active (II) plant lines. 

Figure 6. Maceration of potato tuber tissue pre-incubated for 2 h with 0,05 U/ml of PL3 enzyme activity. Con = Control incubated with the inactivated enzyme.

When Rhizopus sp. 26R was cultivated in the solid substrates without addition of rice bran but composed of only wheat bran and rice husk at the ratio of 18 2. The pectinase activity from the culture was approx. 25-35 unit/ml within 2 days and the production remained constant for 4 days (Figure 3). One gram of raw starch from cassava tuber, 1 g of pectin or 0.5 g of yeast extract was added to the solid substrates in order to induce higher activity of the enzsrme. The results showed that either 1 g raw cassava starch or 1 g pectin that was added to the 20 g solid substrates increased the enzyme activity to 1.7 and 2.4 times, respectively (Figure 3). The production of pectinase in soHd substrates with wheat bran and rice husk could be enhanced with the addition of raw cassava starch and pectin. 

Figure 3 Pectinase activity in 20 g of solid substrates composting of wheat bran, rice bran and rice husk (18 0 2) with the addition of 1 g raw starch from cassava tuber, 1 g pectin or 0.5 g yeast extract.

The pectinases produced in solid substrates from Rhizopus sp. 26R showed the efficiency in enhancing the activity of the glucoamylase in digestion of raw-ground-cassava tuber higher than that of the commercial one. 

Rolfe, M., McLeod, L. E., Pratt, P. F., and Proud, C. G. (2005). Activation of protein synthesis in cardiomyocytes by the hypertrophic agent phenylephrine requires the activation of ERK and involves phosphorylation of tuberous sclerosis complex 2 (TSC2). Biochem. J. 388, 973-984. 

Preparation of Inulin. Comminute the tubers or roots in a food chopper or similar appliance and express the juice with a tincture press, using, if necessary, a small portion of water to complete the extraction. Heat the juice to 60-70° and add milk of lime to about pH 8. Filter and adjust the pH to 7 with oxalic acid. Heat to 70-80°, add activated carbon and filter. Allow the filtrate to stand quiescent overnight, during which time the inulin separates in the form of small spheroids. The yield may be increased by freezing the solution and allowing it to thaw at a low temperature. Filter and wash the inulin with abundant quantities of cold water. 

Enterotoxigenic E. coli B subunits of the heat labile toxin (LTB) Potato tuber Receptor-binding activity. Immunogenic in mice and humans when administered orally. Partially protective in mouse gut fluid assay. 24-26, 90... 

Rotavirus VP7 protein Potato tuber Serum IgG and IgA specific for VP7 IgA had -VP7-neutralizing activity. Immunogenic in mice when delivered orally. 36... 

The introduction of the invertase from yeast alone was not sufficient. Invertase cleaves sucrose to release the two component sugars, glucose and fructose. While fructose can be readily metabolized by fructokinase in potato tubers, there is insufficient hexokinase activity in developing potato tubers to bring the glucose into intermediary metabolism. Therefore, it was necessary to introduce a second transgene, a bacterial glucokinase, in order to ensure that the hexoses became available for subsequent metabolism.25... 

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